Compositions And Methods For Visible-Light-Controlled Ruthenium-Catalyzed Olefin Metathesis

ABSTRACT

The present disclosure provides compositions and methods for metathesizing a first alkenyl or alkynyl group with a second alkenyl or alkynyl group, the composition comprising a ruthenium metathesis catalyst and a photoredox catalyst that is activated by visible light.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of now-allowed U.S. patentapplication Ser. No. 16/597,231, filed Oct. 9, 2019, which claims thebenefit of U.S. Provisional Patent Application No. 62/743,509, filedOct. 9, 2018, which foregoing applications are incorporated by referenceherein in their entireties for any and all purposes.

GOVERNMENT RIGHTS

This invention was made with government support under GM125206 awardedby the National Institutes of Health. The government has certain rightsin the invention.

FIELD OF INVENTION

The present invention provides, inter alia, compositions and methods forcontrollable olefin metathesis.

BACKGROUND OF THE INVENTION

Controlling polymer chain length and the average molecular weightdispersity is important for production of highly functional polymers atindustrial scales. Ring-opening metathesis polymerization (ROMP) is anefficient polymerization method used to manufacture polymers with highfidelity and accuracy. The ring opening metathesis polymerization (ROMP)of alkenes is an important class of chain-growth polymerization thatproduces industrially important products. The driving force of thesereactions is the relief of ring strain in cyclic olefins and a varietyof heterogeneous and homogeneous catalysts have been developed and usedin this context. ROMP is an attractive method to synthesize functionalpolymers as it is robust, produces linear materials with narrowmolecular weight distributions and controlled average molecular weights.However, ROMP is typically activated by metal catalysts that can makecontrolling chain length and molecular weight challenging.

As such, there is an unmet need for methods and compositions thatprecisely tune catalysis of ROMP, which would enable improved control ofpolymer production. The present disclosure is meant to address theselimitations.

SUMMARY OF THE INVENTION

In some embodiments, the disclosure provides compositions formetathesizing a first alkenyl or alkynyl group with a second alkenyl oralkynyl group, the composition comprising a ruthenium metathesiscatalyst and a photoredox catalyst that is activated by visible light.In certain aspects, the visible light has a wavelength of about 350 nmto about 750 nm.

In other embodiments, the disclosure provides methods of spatiallycontrolling a metathesis, comprising forming a mixture of a rutheniummetathesis catalyst, a photoredox catalyst, and one or more compoundssusceptible to metathesis; and applying visible light to one or moreregions of the mixture so as to give rise to one or more metathesizedregions and one or more unmetathesized regions. In certain aspects, thevisible light is applied using a high resolution light source. In otheraspects, at least one of the unmetathesized regions is covered with aphotomask. In further aspects, the photomask is substantially opaque. Inyet other aspects, the substrate is functionalized with the one or morecompounds susceptible to metathesis.

The disclosed technology has application in a broad range of fields,including, e.g., polymer production, polymer patterning,photolithography and 3-D printing, among others. The disclosedtechnology presents numerous advantages over existing approaches, whichadvantages include, for example, minimal reagent requirements, theability to use visible light (thereby reducing or even eliminating theneed for more complicated illumination sources), the ability to utilizea broad range of starting materials as to arrive at a broad range ofproducts, and the ability to exert both temporal and spatial controlover product formation.

BRIEF DESCRIPTION OF THE DRAWINGS

The present application is further understood when read in conjunctionwith the appended drawings. For the purpose of illustrating the subjectmatter, exemplary embodiments of the subject matter are shown in thesedrawings; however, the presently disclosed subject matter is not limitedto the specific methods, devices, and systems disclosed. In addition,the drawings are not necessarily drawn to scale. In the drawings:

FIG. 1 is a schematic showing temporal and spatial control in catalysis.

FIG. 2 is a schematic showing bis(NHC)-ruthenium complexes as latentcatalysts using visible light.

FIG. 3 is a schematic and bar graph showing temporal control over theRCM of diethyl diallylmalonate and corresponding proposed mechanism.

FIG. 4 is a schematic showing the proposed catalytic cycle.

FIG. 5 is a reaction scheme showing the macroscopic patterning ofpoly(dicyclopentadiene).

FIGS. 6A-6C are photographs of polymer patterning and photolithographicolefin metathesis polymerization (PLOMP) using visible light,photomasks, and a blue LED (40 W, Kessil).

FIGS. 7A-7C are photographs of polymer patterning and photolithographicolefin metathesis polymerization (PLOMP) using visible light and bluelaser pointer (200 mW).

FIG. 8 is a reaction scheme showing the microscopic patterning ofpoly(norbornadiene) via PLOMP.

FIGS. 9A-9C are photographs showing polymer patterning andphotolithographic olefin metathesis polymerization (PLOMP) using visiblelight and photomasks and a blue LED (40 W, Kessil).

FIG. 9D is the on and off study for the RCM of dibenzyl diallylmalonate.

FIG. 10 is the cyclic voltammetry spectrum for RuCl₂(CHPh)(IMes)₂ versusAg/AgCl.

FIG. 11 is the cyclic voltammetry spectrum for RuCl₂(CHPh)(IMes)₂ versusAg/AgCl (Differential Scan Rates—Cyclic Voltammetry).

FIG. 12 is the cyclic voltammetry spectrum for RuCl₂(CHPh)(IMes)₂ versusAg/AgCl (Differential Scan Rates—Linear Voltammetry).

FIG. 13 is the cyclic voltammetry spectrum for IMes versus Ag/AgCl.

FIG. 14 is the cyclic voltammetry spectrum for RuCl₂(CHPh)(SIMes)₂versus Ag/AgCl.

FIG. 15 is the cyclic voltammetry spectrum for SIMes versus Ag/AgCl.

FIG. 16 are ¹H-NMR spectra comparing the Ruthenium and TPPT catalystsprior and after blue light irradiation.

FIG. 17 are sections from FIG. 16 showing diagnostic peaks suggestingcomplexation of TPPT to potentially form intermediate VII.

FIG. 18 are ¹H-NMR spectra showing the kinetic NMR spectroscopy of a 1:1solution of TPPT and RuCl₂(CHPh)(IMes)₂ in d-DCM.

FIG. 19 are sections from FIG. 18 showing the diagnostic peaks.

FIG. 20 is a bar graph showing the NMR yield over time of the ringclosing metathesis of diethyl diallylmalonate using RuCl₂(CHPh)(IMes)₂and 2,4,6-triphenylpyrylium tetrafluoroborate alternating cycles ofirradiation and darkness.

FIG. 21 are masks used to prepare the patterns of FIG. 6.

FIGS. 22 and 23 are photographs showing the experimental setup forphotolithography on silicon wafers.

FIGS. 24A-24D are photographs of patterned poly(12, 9, 10 and 11). FIG.24A is a photograph of poly(dicyclopentadiene 12). FIG. 24B is aphotograph of poly(norbornadiene 9).

FIG. 24C is a photograph of poly(1,5-cyclooctadiene 10). FIG. 24D is aphotograph of poly(5-ethylidene-2-norbornene 11).

FIGS. 25A-25C are photographs of poly(dicyclopentadiene 12) illustratingThickness as a function of irradiation time. FIG. 25A is a photographobtained after 5 minutes of irradiation. FIG. 25B is a photographobtained after 15 minutes of irradiation. FIG. 25C is a photographobtained after 60 minutes of irradiation.

FIGS. 26A-26B are photographs of the ROMP of norbornadiene with a foilmask. FIG. 26A is before the wash with dichloromethane and FIG. 26B isafter the wash.

FIGS. 27A-27D are photographs of the ROMP of norbornadiene (FIG. 27A),COD (FIG. 27B), 5-ethylidene-2-norbornene (FIG. 27C), anddicyclopentadiene (FIG. 27D), using a black paper mask. Photographs onthe left are immediately after irradiation and photographs on the rightare 5 hours after irradiation.

FIGS. 28A-28C are photographs of the ROMP of 5-ethylidene-2-norbornene(FIG. 28A) and dicyclopentadiene (FIGS. 28B and 28C). Photographs on theleft are immediately after irradiation and photographs on the right are5 hours after irradiation.

FIGS. 29A-29C are photographs of the ROMP using sequential patterning.FIG. 29A is a photograph after a first polymerization using a firstmask. FIG. 29B is a photograph after the second polymerization using asecond mask. FIG. 29C is a photograph 5 hours after the secondpolymerization.

FIGS. 30A and 30B are photographs of the ROMP of dicyclopentadiene usingblue-light laser pointer instead of Kessil lamps.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The present invention may be understood more readily by reference to thefollowing description taken in connection with the accompanying Figuresand Examples, all of which form a part of this disclosure. It is to beunderstood that this invention is not limited to the specific products,methods, conditions or parameters described or shown herein, and thatthe terminology used herein is for the purpose of describing particularembodiments by way of example only and is not intended to be limiting ofany claimed invention. Similarly, unless specifically otherwise stated,any description as to a possible mechanism or mode of action or reasonfor improvement is meant to be illustrative only, and the inventionherein is not to be constrained by the correctness or incorrectness ofany such suggested mechanism or mode of action or reason forimprovement. Throughout this text, it is recognized that thedescriptions refer to compositions and methods of making and using saidcompositions. That is, where the disclosure describes or claims afeature or embodiment associated with a composition or a method ofmaking or using a composition, it is appreciated that such a descriptionor claim is intended to extend these features or embodiment toembodiments in each of these contexts (i.e., compositions, methods ofmaking, and methods of using).

In the present disclosure the singular forms “a,” “an,” and “the”include the plural reference, and reference to a particular numericalvalue includes at least that particular value, unless the contextclearly indicates otherwise. Thus, for example, a reference to “amaterial” is a reference to at least one of such materials andequivalents thereof known to those skilled in the art, and so forth.

When a value is expressed as an approximation by use of the descriptor“about,” it will be understood that the particular value forms anotherembodiment. In general, use of the term “about” indicates approximationsthat can vary depending on the desired properties sought to be obtainedby the disclosed subject matter and is to be interpreted in the specificcontext in which it is used, based on its function. The person skilledin the art will be able to interpret this as a matter of routine. Insome cases, the number of significant figures used for a particularvalue may be one non-limiting method of determining the extent of theword “about.” In other cases, the gradations used in a series of valuesmay be used to determine the intended range available to the term“about” for each value. Where present, all ranges are inclusive andcombinable. That is, references to values stated in ranges include everyvalue within that range.

It is to be appreciated that certain features of the invention whichare, for clarity, described herein in the context of separateembodiments, may also be provided in combination in a single embodiment.That is, unless obviously incompatible or specifically excluded, eachindividual embodiment is deemed to be combinable with any otherembodiment(s) and such the combination is considered to be anotherembodiment. Conversely, various features of the invention that are, forbrevity, described in the context of a single embodiment, may also beprovided separately or in any sub-combination. Finally, while anembodiment may be described as part of a series of steps or part of amore general structure, each said step may also be considered anindependent embodiment in itself, combinable with others.

The transitional terms “comprising,” “consisting essentially of,” and“consisting” are intended to connote their generally in acceptedmeanings in the patent vernacular; that is, (i) “comprising,” which issynonymous with “including,” “containing,” or “characterized by,” isinclusive or open-ended and does not exclude additional, unrecitedelements or method steps; (ii) “consisting of” excludes any element,step, or ingredient not specified in the claim; and (iii) “consistingessentially of” limits the scope of a claim to the specified materialsor steps “and those that do not materially affect the basic and novelcharacteristic(s)” of the claimed invention. Embodiments described interms of the phrase “comprising” (or its equivalents), also provide, asembodiments, those which are independently described in terms of“consisting of” and “consisting essentially of” For those embodimentsprovided in terms of “consisting essentially of” the basic and novelcharacteristic(s) is the facile operability of the methods (and thesystems used in such methods and the compositions derived therefrom) toprepare and use the inventive materials, and the materials themselves,where the methods and materials are capable of delivering thehighlighted properties using only the elements provided in the claims.That is, while other materials may also be present in the inventivecompositions, the presence of these extra materials is not necessary toprovide the described benefits of those compositions or devices (i.e.,the effects may be additive) and/or these additional materials do notcompromise the performance of the product compositions or devices.Similarly, where additional steps may also be employed in the methods,their presence is not necessary to achieve the described effects orbenefits and/or they do not compromise the stated effect or benefit.

When a list is presented, unless stated otherwise, it is to beunderstood that each individual element of that list, and everycombination of that list, is a separate embodiment. For example, a listof embodiments presented as “A, B, or C” is to be interpreted asincluding the embodiments, “A,” “B,” “C,” “A or B,” “A or C,” “B or C,”or “A, B, or C.” This includes, without limitation, that a genuspresenting multiple parameters, each parameter presenting multipleoptions, represents that collection of individual embodiments includingany and every combination of these variables and options. By means ofillustration only, a composition described in terms of two variables Aand B, each variable presenting two options (a) and (b), includes, asindependent embodiments, the subgenera A(a)−B(a), A(a)−B(b), A(b)−B(a),and A(b)−B(b). This principle can be applied to larger numbers ofvariables and options, such that any one or more of these variable oroptions can be independently claimed or excluded. Likewise, a definitionsuch as C₁₋₃-alkyl includes C₁-alkyl, C₂-alkyl, C₃-alkyl, C₁₋₂-alkyl,C₂₋₃-alkyl, and C₁₋₃-alkyl as separate embodiments.

Because each individual element of a list, and every combination of thatlist, is a separate embodiment, it should be apparent that anydescription of a genus or subgenus also included those embodiments whereone or more of the elements are excluded, without the need for thedisclosure of the exclusion. For example, a genus described ascontaining elements “A, B, C, D, E, or F” also includes the embodimentsexcluding one or more of these elements, for example “A, C, D, E, or F;”“A, B, D, E, or F;” “A, B, C, E, or F;” “A, B, C, D, or F;” “A, B, C, D,or E;” “A, D, E, or F;” “A, B, C, or F;” “A, E, or F;” “A, C, E, or F;”“A or F;” etc., without the need to explicitly delineate the exclusions.

The term “alkyl” as used herein refers to a linear, branched, or cyclicsaturated hydrocarbon group typically although not necessarilycontaining 1 to about 30 carbon atoms, in some cases, from 1 to about 12carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl,isobutyl, t-butyl, octyl, decyl, and the like, as well as cycloalkylgroups such as cyclopentyl, cyclohexyl and the like, or in other casesfrom about 12 to about 24 or 30 carbon atoms (e.g., oleic and otherfatty or saturated acids). Generally, although again not necessarily,alkyl groups herein can also contain 1 to about 12 carbon atoms or 1 to6 carbon atoms. The term “cycloalkyl” intends a cyclic alkyl group,typically having 4 to 8, preferably 5 to 7, carbon atoms. The term“substituted alkyl” refers to alkyl groups substituted with one or moresubstituent groups, and the terms “heteroatom-containing alkyl” and“heteroalkyl” refer to alkyl groups in which at least one carbon atom isreplaced with a heteroatom. If not otherwise indicated, the terms“alkyl” and “lower alkyl” include linear, branched, cyclic,unsubstituted, substituted, and/or heteroatom-containing alkyl and loweralkyl groups, respectively.

The term “haloalkyl” as used herein refers to an alkyl groups asdescribed, wherein one or more hydrogen atom is replaced with a halo. Insome embodiments, haloalkyl includes an alkyl group substituted with oneor more F. In some embodiments, haloalkyl includes an alkyl groupsubstituted with one or more Br. In some embodiments, haloalkyl includesan alkyl group substituted with one or more Cl. In some embodiments,haloalkyl includes an alkyl group substituted with one or more I.Examples of haloalkyl groups include fluorinated alkyl groups including,without limitation, CF₃, CF₂H, CFH₂, CH₂CF₃, CH₂CH₂CF₃, CH₂CH₂CH₂CF₃,and CH₂CH₂CH₂CH₂CF₃.

The term “alkenyl” as used herein refers to a linear, branched, orcyclic hydrocarbon group of 2 to about 30 carbon atoms containing atleast one double bond, such as ethenyl, n-propenyl, isopropenyl,n-butenyl, isobutenyl, octenyl, decenyl, tetradecenyl, hexadecenyl,eicosenyl, tetracosenyl, and the like. In some embodiments, alkenylgroups contain 2 to about 12 carbon atoms, preferably 2 to about 6carbon atoms. “Alkenyl” also includes vinyl groups, wherein the doublebond is at a terminal location of the molecule. The term “substitutedalkenyl” refers to alkenyl groups substituted with one or moresubstituent groups. If not otherwise indicated, the term “alkenyl”includes linear, branched, cyclic, unsubstituted, and/or substitutedalkenyl groups, respectively.

The term “alkynyl” as used herein refers to a linear, branched, orcyclic hydrocarbon group of 2 to about 30 carbon atoms containing atleast one triple bond, such as ethynyl, n-propynyl, isopropynyl,n-butynyl, isobutynyl, octynyl, decynyl, tetradecynyl, hexadecynyl,eicosynyl, tetracosynyl, and the like. In some embodiments, alkynylgroups contain 2 to about 12 carbon atoms, preferably 2 to about 6carbon atoms. The term “substituted alkynyl” refers to alkynyl groupssubstituted with one or more substituent groups. If not otherwiseindicated, the term “alkynyl” includes linear, branched, cyclic,unsubstituted, and/or substituted alkynyl groups, respectively.

The term “alkoxy” as used herein intends an alkyl group bound through asingle, terminal ether linkage; that is, an “alkoxy” group may berepresented as —O-alkyl where alkyl is as defined above. An “alkoxy”group includes an alkoxy group containing 1 to 6 carbon atoms, i.e.,methoxy, ethoxy, propoxy, butoxy, pentoxy, or hexoxy.

The term “aryl” as used herein, and unless otherwise specified, refersto an aromatic substituent or structure containing a single aromaticring or multiple aromatic rings that are fused together, directlylinked, or indirectly linked (such that the different aromatic rings arebound to a common group such as a methylene or ethylene moiety). In someembodiments, the aryl ring is unfused. In other embodiments, the aryl isa fused aryl. In further embodiments, the aryl is a bridged aryl. Unlessotherwise modified, the term “aryl” refers to carbocyclic structures.Preferred aryl groups contain 5 to 24 carbon atoms, and particularlypreferred aryl groups contain 5 to 14 carbon atoms. Exemplary arylgroups contain one aromatic ring or two fused or linked aromatic rings,e.g., phenyl, naphthyl, biphenyl, diphenylether, diphenylamine,benzophenone, and the like. “Substituted aryl” refers to an aryl moietysubstituted with one or more substituent groups.

The term “acyl” refers to substituents having the formula —(CO)-alkyl(alkylcarbonyl), —(CO)-aryl (arylcarbonyl), or —(CO)-aralkyl, and theterm “acyloxy” refers to substituents having the formula —O(CO)-alkyl,—O(CO)-aryl, or —O(CO)-aralkyl, wherein “alkyl,” “aryl, and “aralkyl”are as defined above.

The terms “halo,” “halide,” and “halogen” are used in the conventionalsense to refer to a chloro, bromo, fluoro, or iodo substituent.

The term “heteroatom-containing” refers to a hydrocarbon molecule or amolecular fragment in which one or more carbon atoms is replaced with anatom other than carbon, e.g., nitrogen, oxygen, sulfur, phosphorus orsilicon, typically nitrogen, oxygen or sulfur. Similarly, the term“heteroalkyl” refers to an alkyl substituent that isheteroatom-containing, the term “heterocyclic” refers to a cyclicsubstituent that is heteroatom-containing, the terms “heteroaryl” andheteroaromatic” respectively refer to “aryl” and “aromatic” substituentsthat are heteroatom-containing, and the like. It should be noted that a“heterocyclic” group or compound may or may not be aromatic, and furtherthat “heterocycles” may be monocyclic, bicyclic, or polycyclic asdescribed above with respect to the term “aryl.”

Non-limiting examples of heteroaryl groups include azepinyl, acridinyl,carbazolyl, cinnolinyl, furanyl, furazanyl, furanonyl, isothiazolyl,imidazolyl, indazolyl, indolyl, isoindolyl, indolinyl, isoindolinyl,isoquinolyl, indolizinyl, isoxazolyl, naphthyridinyl, oxadiazolyl,oxazolyl, oxiranyl, phenazinyl, phenothiazinyl, phenoxazinyl,phthalazinyl, pteridinyl, purinyl, pyranyl, pyrrolyl, pyrrolidinyl,pyrazolyl, pyridinyl, pyrazinyl, pyrimidinyl, pyridazinyl, quinazolinyl,quinoxalinyl, quinolinyl, isoquinolinyl, tetrahydroquinolinyl,thiazolyl, thiadiazolyl, thiapyranyl, triazolyl, tetrazolyl, triazinyl,and thiophenyl. Non-limiting examples of heteroatom-containing alicyclicgroups are pyrrolidino, morpholino, piperazino, and piperidino.

The term “aryloxy” as used herein refers to a O-aryl group, wherein thearyl group is defined herein.

The term “aralkyl” refers to an alkyl group with an aryl substituent(-alkyl-aryl), wherein aryl and alkyl are defined herein. Similarly, theterm “aralkyloxy” refers to an alkyl group with a O-aryl group-alkyl-O-aryl), wherein aryl and alkyl are defined herein.

The term “acyloxy” as used herein refers to an —O-acyl, wherein acyl isdefined herein. The term “acyloxy” includes groups such asalkylcarbonyloxy (—OC(O)alkyl), arylcarbonyloxy (—OC(O)aryl),alkoxycarbonyl (—C(O)Oalkyl), and aryloxycarbonyl (—C(O)Oaryl), whereinthe alkyl, aryl, and alkoxy groups are defined herein.

The term “halocarbonyl” as used herein refers to the —C(O)—X, wherein Xis a halo group defined herein.

The term “carboxy” refers to a —C(O)OH, carboxylato or “carboxyl” refersto a —C(O)O—, and carbamoyl refers to a —C(O)NH₂ group.

The terms mono-(alkyl)-substituted carbamoyl and di-(alkyl)-substitutedcarbamoyl refers to —C(O)NH(alkyl) and —C(O)N(alkyl)₂ groups,respectively, wherein the alkyl groups are defined herein andindependently chosen.

The terms “mono-(aryl)-substituted carbamoyl”, di-(aryl)substitutedcarbamoyl,” and “, di-N-(alkyl),N-(aryl)-substituted carbamoyl” refer to—C(O)NH-aryl, —C(O)N(aryl)₂), and —C(O)N(aryl)(alkyl) groups, whereinalkyl and aryl are defined herein and independently chosen.

The term “thiocarbamoyl” refers to the —C(S)NH₂ group. Similarly, theterms mono-(alkyl)-substituted thiocarbamoyl refers to the—C(S)NH(alkyl)) and the di-(alkyl)-substituted thiocarbamoyl refers tothe —C(S)N(alkyl)₂), wherein the alkyl group is defined herein and isindependently selected.

The terms “mono-(aryl)substituted thiocarbamoyl” and“di-(C₅₋₂₄aryl)-substituted thiocarbamoyl” refers to —C(S)NH-aryl and—C(S)N(C₅₋₂₄aryl)₂ groups, wherein the aryl groups are defined hereinand are independently chosen.

The term “amino” refers to the NH₂ group. Similarly, alkyl-substitutedamino groups include “mono-(alkyl)-substituted amino” anddi-(alkyl)-substituted amino, wherein the alkyl groups are definedherein and independently chosen. Further, aryl-substituted amino groupsinclude mono-(aryl)substituted amino and di-(aryl)-substituted amino,wherein the aryl groups are defined herein and independently chosen.

The term “amido” refers to the —NHC(O)— group, and includes alkylamidoand arylamido groups. The terms “alkylamido” and “arylamido” refers to—NHC(O)alkyl and —NHC(O)aryl, wherein alkyl and aryl are defined herein.

The terms “alkylthio” and “arylthiol” as used herein refer to —S-alkyland —S-aryl, groups, respectively, wherein alkyl and aryl are definedherein.

The term “sulfonyl” refers to the SO₂ group.

The term “germyl” refers to a GeR^(Z) ₃ group, the term “stannyl” refersto a SnR^(Z) ₃ group, the term “boryl” refers to a BH₂, BH(R^(Z)),B(R^(Z))₂, or B(OR^(Z))₂, group, and “silyl” refers to a SiR^(Z) ₃,wherein R^(Z) is, independently, in each instance C₁₋₁₂alkyl or aryl asdefined herein.

By “substituted” as in “substituted alkyl,” “substituted aryl,” and thelike, as alluded to in some of the aforementioned definitions, is meantthat in the alkyl, aryl, heteroaryl, or other moiety, at least onehydrogen atom bound to a carbon (or other) atom is replaced with one ormore non-hydrogen substituents. Examples of such substituents include,without limitation, halo (e.g., F, Cl, Br, I), OH, sulfhydryl, alkoxy,aryloxy, aralkyloxy, acyl (including alkylcarbonyl, arylcarbonyl,acyloxy (alkylcarbonyloxy and arylcarbonyloxy), alkoxycarbonyl,aryloxycarbonyl, halocarbonyl, carboxy, carboxylate), carbamoyl,mono-(alkyl)-substituted carbamoyl, di-(alkyl)-substituted carbamoyl,mono-(aryl)-substituted carbamoyl, di-(aryl)substituted,di-N-(alkyl),N-(aryl)-substituted carbamoyl, thiocarbamoyl,mono-(alkyl)-substituted thiocarbamoyl, di-(alkyl)-substitutedthiocarbamoyl, mono-(aryl)substituted thiocarbamoyl,di-(aryl)-substituted thiocarbamoyl, di-N-(alkyl), N-(aryl)-substitutedthiocarbamoyl, CN, OCN, thiocyanato, formyl, C(S)H, NH₂,mono-(alkyl)-substituted amino, di-(alkyl)-substituted amino,mono-(aryl)substituted amino, di-(aryl)-substituted amino, alkylamido,arylamido, NO₂, NO, alkylthio (—S-alkyl), arylthio (—S-aryl), alkyl,alkenyl, alkynyl, aryl, and aralkyl. Within these substituentstructures, the “alkyl,” “alkylene,” “alkenyl,” “alkenylene,” “alkoxy,”“aromatic,” “aryl,” “aryloxy,” and “aralkyl” moieties may be optionallyfluorinated or perfluorinated.

“Optional” or “optionally” means that the subsequently describedcircumstance may or may not occur, so that the description includesinstances where the circumstance occurs and instances where it does not.For example, the phrase “optionally substituted” means that anon-hydrogen substituent may or may not be present on a given atom, and,thus, the description includes structures wherein a non-hydrogensubstituent is present and structures wherein a non-hydrogen substituentis not present.

Compositions

The present disclosure is related to compositions and methods formetathesizing unsaturated compounds using one or more of a rutheniumcatalyst, a photoredox catalyst, and visible light. In some embodiments,it is believed that the mode of activation is the energy or electrontransfer from/to the excited state of the photocatalyst that inducesligand dissociation and thus starts metathesis. In other embodiments,upon irradiation by visible light, the photocatalyst is excited byabsorption of a photon. In further embodiments, it also is believed thatthe methods induce dissociation of one of the carbene ligands from thelatent metathesis catalyst, thus generating the active species that canstart to promote ROMP or its mechanistically related congeners. In yetother embodiments, turning the light off leads to re-coordination of thecarbene ligand onto the ruthenium catalyst and therefore is thought toshut down metathesis since the active catalyst is no longer present inthe media. As a consequence, in some embodiments, the methods permitcontrolling initiation of the ROMP and accurately controlling the lengthof the polymer chains by modulating the irradiation time—these featuresthat cannot be achieved with current systems in ROMP, and furtherexpands the scope and ease of production of industrially relevantmaterials.

According to some embodiments, this disclosure relies on the activationof an external photocatalyst in order to activate the rutheniummetathesis catalyst and therefore start the polymerization event via anon and off process. In other embodiments, this disclosure provides aphotocatalyst that is only catalytically-active upon absorption ofvisible light, providing an external handle for precisely controllinginitiation and termination of ROMP. As such, in further embodiments,this disclosure provides a switchable photocatalyst for the industrialfabrication of polymers with controlled weights, chain length, anddispersity. In yet other embodiments, the photoredox-promoted ringopening metathesis polymerization provides increased control overinitiation and should serve as a tool that enables to precisely controlthe length of the polymer chains, and thus the properties of thepolymer, by controlling the irradiation time.

Accordingly, one embodiment of the present disclosure is a compositionfor olefin metathesis comprising a latent metathesis catalyst, and aphotocatalyst, wherein the olefin metathesis is controlled by visiblelight irradiation. Thus, in some embodiments, the present disclosureprovides the use of a latent ruthenium metathesis catalyst bearing twopoorly dissociable carbene ligands that is not active for metathesis atambient temperature without external activation.

As used herein, an “olefin metathesis” is an organic reaction thatentails the redistribution of fragments of alkenes (olefins) by thescission and regeneration of carbon-carbon double bonds. As used herein,a “latent catalyst” is a catalyst that can be “switched on” from aninactive state by application of an external trigger such as, e.g., heator light.

In other embodiments of the present disclosure, compositions for alkynemetathesis are provided comprising a latent metathesis catalyst, and aphotocatalyst, wherein the alkyne metathesis is controlled by visiblelight irradiation.

In further embodiments of the present disclosure, compositions for mixedolefin/alkyne metathesis are provided comprising a latent metathesiscatalyst, and a photocatalyst, wherein the olefin/alkyne metathesis iscontrolled by visible light irradiation.

The metathesis described herein is performed using a rutheniummetathesis catalyst and a photoredox catalyst that is activated byvisible light. The terms “photocatalyst” and “photoredox catalyst” areinterchangeable and refer to a catalyst that is activated by visiblelight. “Visible light” as used herein refers to light that has awavelength of about 350 nm to about 750 nm. In some embodiments, thevisible light has a wavelength of about 350 to about 700 nm, about 350to about 650 nm, about 350 to about 600 nm, about 350 to about 550 nm,about 350 to about 500 nm, about 300 to about 450 nm, about 300 to about400 nm, about 400 to about 750 nm, about 450 to about 750 nm, about 500to about 750 nm, about 550 to about 750 nm, about 600 to about 750 nm,or about 650 to about 750 nm. In further embodiments, the visible lightwavelength is about 400 to about 500 nm, about 410 to about 490 nm,about 420 to about 450 nm, about 430 to about 450 nm, or about 44 nm.The term “activated by visible light” refers to the state of photoredoxcatalyst going from unreactive to reactive.

The inventors determined that photoredox catalysts that are highlyoxidizing contribute to the ease of metathesis. Thus, in someembodiments, the photoredox catalyst has an oxidizing potential of about1.5 to about 3 volts, i.e., “highly oxidizing”. In further embodiments,the oxidizing potential of the photoredox catalyst is about 1.5 to about2.75 volts, about 1.5 to about 2.5 volts, about 1.5 to about 2 volts,about 1.75 to about 3 volts, about 1.75 to about 2.75 volts, about 1.75to about 2.5 volts, about 1.75 to about 2 volts, about 2 to about 3volts, or about 2 to about 2.5 volts. In other embodiments, theoxidizing potential is about 1.5 volts, 1.6 volts, 1.7 volts, 1.75volts, 1.8 volts, 1.9 volts, 2 volts, 2.1 volts, 2.2 volts, 2.3 volts,2.4 volts, 2.5 volts, 2.6 volts, 2.7 volts, 2.8 volts, 2.9 volts, orabout 3 volts.

In some embodiments, the photoredox catalyst is of Formula (A):

In these compounds, R⁶, R⁷, and R⁸ are, independently, in eachoccurrence, H, halo, optionally substituted C₁₋₆alkyl, optionallysubstituted C₁₋₆alkoxy, optionally substituted C₁₋₆haloalkyl, CN, NO₂,optionally substituted aryl, optionally substituted heteroaryl,optionally substituted vinyl, C(O)OR^(L), CON(R^(L))₂, or C(O)R^(L),where R^(L) is optionally substituted H, C₁₋₆alkyl, C₁₋₆heteroalkyl,C₃₋₈cycloalkyl, aryl, or heteroaryl. In some embodiments, one, two, orall of R⁶, R⁷, and R⁸ are halo. In other embodiments, one, two, or allof R⁶, R⁷, and R⁸ are optionally substituted C₁₋₆alkyl. In furtherembodiments, one, two, or all of R⁶, R⁷, and R⁸ are optionallysubstituted C₁₋₆alkoxy. In other embodiments, one, two, or all of R⁶,R⁷, and R⁸ are optionally substituted C₁₋₆haloalkyl. In furtherembodiments, one two, or all of R⁶, R⁷, and R⁸ are CN. In still otherembodiments, one two, or all of R⁶, R⁷, and R⁸ are NO₂. In yet furtherembodiments, one two, or all of R⁶, R⁷, and R⁸ are optionallysubstituted aryl. In other embodiments, one two, or all of R⁶, R⁷, andR⁸ are optionally substituted heteroaryl. In further embodiments,embodiments, one two, or all of R⁶, R⁷, and R⁸ are optionallysubstituted vinyl. In still other embodiments, one two, or all of R⁶,R⁷, and R⁸ are C(O)OR^(L), where R^(L) is optionally substitutedC₁₋₆alkyl, C₁₋₆heteroalkyl, C₃₋₈cycloalkyl, aryl, or heteroaryl. In yetfurther embodiments, one, two, or all of R⁶, R⁷, and R⁸ are CON(R^(L))₂,where R^(L) is H, optionally substituted C₁₋₆alkyl, C₁₋₆heteroalkyl,C₃₋₈cycloalkyl, aryl, or heteroaryl. In other embodiments, one, two, orall of R⁶, R⁷, and R⁸ are C(O)R^(L), where R^(L) is H, optionallysubstituted C₁₋₆alkyl, C₁₋₆heteroalkyl, C₃₋₈cycloalkyl, aryl, orheteroaryl. In yet other embodiments, R⁶, R⁷, and R⁸ are H or halo. Inother embodiments, R⁶, R⁷, and R⁸ are H or optionally substitutedC₁₋₆alkyl. In further embodiments, R⁶, R⁷, and R⁸ are H or optionallysubstituted C₁₋₆alkoxy. In other embodiments, R⁶ is H. In furtherembodiments, R⁶ is halo. In yet other embodiments, R⁶ is optionallysubstituted C₁₋₆alkyl. In still further embodiments, R⁶ is C₁₋₆alkoxy.In other embodiments, R⁶ is optionally substituted C₁₋₆haloalkyl. Infurther embodiments, R⁶ is CN. In still other embodiments, R⁶ is NO₂. Inyet further embodiments, R⁶ is optionally substituted aryl. In otherembodiments, R⁶ is optionally substituted heteroaryl. In still furtherembodiments, R⁶ is optionally substituted vinyl. In still otherembodiments, R⁶ is C(O)OR^(L), wherein R^(L) is defined herein. In yetfurther embodiments, R⁶ is CON(R^(L))₂, wherein R^(L) is defined herein.In still other embodiments, R⁶ is C(O)R^(L), wherein R^(L) is definedherein. In other embodiments, R⁷ is H. In further embodiments, R⁷ ishalo. In yet other embodiments, R⁷ is optionally substituted C₁₋₆alkyl.In still further embodiments, R⁷ is optionally substituted C₁₋₆alkoxy.In other embodiments, R⁷ is optionally substituted C₁₋₆haloalkyl. Infurther embodiments, R⁷ is CN. In still other embodiments, R⁷ is NO₂. Inyet further embodiments, R⁷ is optionally substituted aryl. In otherembodiments, R⁷ is optionally substituted heteroaryl. In still furtherembodiments, R⁷ is optionally substituted vinyl. In still otherembodiments, R⁷ is C(O)OR^(L), wherein R^(L) is defined herein. In yetfurther embodiments, R⁷ is CON(R^(L))₂, wherein R^(L) is defined herein.In still other embodiments, R⁷ is C(O)R^(L), wherein R^(L) is definedherein. In other embodiments, R⁸ is H. In further embodiments, R⁸ ishalo. In yet other embodiments, R⁸ is optionally substituted C₁₋₆alkyl.In still further embodiments, R⁸ is optionally substituted C₁₋₆alkoxy.In other embodiments, R⁸ is optionally substituted C₁₋₆haloalkyl. Infurther embodiments, R⁸ is CN. In still other embodiments, R⁸ is NO₂. Inyet further embodiments, R⁸ is optionally substituted aryl. In otherembodiments, R⁸ is optionally substituted heteroaryl. In still furtherembodiments, R⁸ is optionally substituted vinyl. In still otherembodiments, R⁸ is C(O)OR^(L), wherein R^(L) is defined herein. In yetfurther embodiments, R⁸ is CON(R^(L))₂, wherein R^(L) is defined herein.In still other embodiments, R⁸ is C(O)R^(L), wherein R^(L) is definedherein.

m, n, and p are, independently, 0 to 5. In some embodiments, m, n, and pare 1. In other embodiments, m, n, and p are 2. In further embodiments,m, n, and p are 3. In yet other embodiments, m, n, and p are 4. In stillother embodiments, m, n, and p are 5. In other embodiments, m is 0. Infurther embodiments, m is 1. In still other embodiments, m is 2. In yetfurther embodiments, m is 3. In other embodiments, m is 4. In furtherembodiments, m is 5. In other embodiments, n is 0. In furtherembodiments, n is 1. In still other embodiments, n is 2. In yet furtherembodiments, n is 3. In other embodiments, n is 4. In furtherembodiments, n is 5. In other embodiments, p is 0. In furtherembodiments, p is 1. In still other embodiments, p is 2. In yet furtherembodiments, p is 3. In other embodiments, p is 4. In furtherembodiments, p is 5.

X is O or S. In some embodiments, X is O. In other embodiments, X is S.

Y is a counter anion. In some embodiments, Y is tetrafluoroborate (BF₄),hexafluorophosphate (PF₆), SbF₆, B(optionally substituted aryl)₄, ClO₄⁻, halo, or an anion where the conjugate acid has a pKa lower than 4.5.In some embodiments, Y is BF₄. In other embodiments, Y is PF₆. Infurther embodiments, Y is SbF₆. In still other embodiments, Y isB(optionally substituted aryl)₄, where optionally substituted aryl isdefined herein. In some embodiments, Y is B(phenyl)₄ orB(3,5-bis(trifluoromethyl)phenyl)₄. In other embodiments, Y is ClO₄ ⁻.In yet further embodiments, Y is halo, such as F, Cl, Br, or I. Incertain embodiments, Y is Br. In other embodiments, Y is Cl. In stillfurther embodiments, Y is I. In other embodiments, Y is an anion wherethe conjugate acid has a pKa lower than 4.5 such as triflate (CF₃SO₃ ⁻)and p-toluenesulfonate (p-CH₃—C₆H₄—SO₃ ⁻).

In certain embodiments, the photoredox catalyst is:

In other embodiments, the photoredox catalyst is 2,4,6-triphenylpyryliumtetrafluoroborate (TPPT):

In further embodiments, the photoredox catalyst is

In yet other embodiments, the photoredox catalyst is:

In still further embodiments, the photoredox catalyst is:

The metathesis of the disclosure also comprises the inclusion of aruthenium catalyst. In some embodiments, the ruthenium catalyst is alatent ruthenium catalyst. The term “latent” as used herein refers tothe state of the catalyst when it is inactivated, i.e., inactive orextremely sluggish. In some aspects, it is believed that the latent formof the ruthenium catalyst converts to an activated or active version ofthe ruthenium catalyst upon loss of one or more of its ligands. In someaspects, this loss of ligand is believed to arise by interaction of theRu catalyst with the excited state of the photocatalyst leading toligand oxidation and dissociation from Ru. In some embodiments, theruthenium catalyst of Formula (I):

In the structure of Formula (I), R^(L) is H, C₁₋₆alkyl, C₂₋₆alkenyl,aryl, or heteroaryl. In some embodiments, R¹ is H. In furtherembodiments, R¹ is C₁₋₆alkyl, such as methyl, ethyl, propyl, butyl,pentyl, or hexyl. In other embodiments, le is C₂₋₆alkenyl, such asethenyl, propenyl, butenyl, pentenyl, or hexenyl. In furtherembodiments, le is aryl such as a C₅₋₂₄ aryl, more preferably C₅₋₁₄aryl. In other embodiments, the aryl is an optionally substitutedphenyl, naphthyl, or biphenyl. In yet further embodiments, R¹ is phenyl.In yet other embodiments, R¹ is heteroaryl such as azepinyl, acridinyl,carbazolyl, cinnolinyl, furanyl, furazanyl, furanonyl, isothiazolyl,imidazolyl, indazolyl, indolyl, isoindolyl, indolinyl, isoindolinyl,isoquinolyl, indolizinyl, isoxazolyl, naphthyridinyl, oxadiazolyl,oxazolyl, oxiranyl, phenazinyl, phenothiazinyl, phenoxazinyl,phthalazinyl, pteridinyl, purinyl, pyranyl, pyrrolyl, pyrrolidinyl,pyrazolyl, pyridinyl, pyrazinyl, pyrimidinyl, pyridazinyl, quinazolinyl,quinoxalinyl, quinolinyl, isoquinolinyl, tetrahydroquinolinyl,thiazolyl, thiadiazolyl, thiapyranyl, triazolyl, tetrazolyl, triazinyl,or thiophenyl.

R² to R⁵ are, independently in each occurrence, H, C₁₋₆alkyl,C₁₋₆alkoxy, halo, or aryl. In some embodiments, R² to R⁵ are H. Infurther embodiments, R² to R⁵ are, independently in each occurrence, Hor C₁₋₆alkyl. In other embodiments, R² to R⁵ are, independently in eachoccurrence, H or C₁₋₆alkoxy. In further embodiments, R² to R⁵ are,independently in each occurrence, H or halo. In yet other embodiments,R² to R⁵ are, independently in each occurrence, H or aryl.

w to z are, independently, 0 to 5. In some embodiments, w is 0 to 5. Inother embodiments, w is 1. In further embodiments, w is 2. In yet otherembodiments, w is 3. In still further embodiments, w is 4. In otherembodiments, x is 5. In some embodiments, x is 0 to 5. In otherembodiments, x is 1. In further embodiments, x is 2. In yet otherembodiments, x is 3. In still further embodiments, x is 4. In otherembodiments, x is 5. In some embodiments, y is 0 to 5. In otherembodiments, y is 1. In further embodiments, y is 2. In yet otherembodiments, y is 3. In still further embodiments, y is 4. In otherembodiments, y is 5. In some embodiments, z is 0 to 5. In otherembodiments, z is 1. In further embodiments, z is 2. In yet otherembodiments, z is 3. In still further embodiments, z is 4. In otherembodiments, z is 5. In some embodiments, w, x, y, and z are 0. In otherembodiments, w, x, y, and z are 1. In further embodiments, w, x, y, andz are 2. In yet other embodiments, w, x, y, and z are 3. In stillfurther embodiments, w, x, y, and z are 4.

In some embodiments, the ruthenium catalyst is:

In other embodiments, the ruthenium catalyst is:

In other embodiments, the ruthenium catalyst is:

In other embodiments, the ruthenium catalyst is:

For any one of the compositions or methods disclosed above, in someembodiments, the latent metathesis catalyst is a bis(NHC)-rutheniumcomplex. Non-limiting examples of a bis(NHC)-ruthenium complex includeIMes₂RuCl₂CHPh and SIMes₂RuCl₂CHPh. In certain aspects, thebis(NHC)-ruthenium complex is IMes₂RuCl₂CHPh. In other aspects, thephotocatalyst is a highly oxidizing photocatalyst, which is selectedfrom acridinium and pyrylium derivatives. In further aspects, thephotocatalyst is 2,4,6-tri-phenylpyrylium tetrafluoroborate (TPPT).

In some embodiments, the compositions comprise IMes₂RuCl₂CHPh and2,4,6-tri-phenylpyrylium tetrafluoroborate (TPPT).

A scope of the metathesis described herein is not limited to thosedisclosed herein. Instead, one of skill in the art would be able toselect suitable compounds to utilize in the metathesis described herein.In general, the compounds that may be metathesized according to thedisclosure contain at least one point of unsaturation. The term“unsaturation” as used herein refers to a double or triple bond or anycombination thereof. The term “double bond” as noted herein refers to aC═C group and a “triple bond” refers to a C≡C bond, either of whichbeing contained in a chemical compound. The chemical compound containinga double bond is known in the art as an “alkene” or “olefin,” whichterms may be used interchangeably. Thus, a substituent on a moleculehaving a double bond is an “alkenyl” group. Similarly, a chemicalcompound containing a triple bond is known in the art as an “alkyne.”Thus, a substituent on a molecule having a triple bond is an “alkynyl”group. In some embodiments, the metathesis is performed on a compoundhaving two points of unsaturation. In other embodiments, the metathesisis performed on a first compound having at least one point ofunsaturation and a second compound having at least one point ofunsaturation.

As such, the present disclosure is directed to metathesizing a firstalkenyl or alkynyl group with a second alkenyl or alkynyl group. In someembodiments, the present disclosure provides metathesizing a firstalkenyl group with a second alkenyl group. In other embodiments, thepresent disclosure provides metathesizing a first alkenyl group with afirst alkynyl group. In further embodiments, the present disclosureprovides metathesizing a first alkynyl group and a second alkynyl group.In further embodiments, the present disclosure provides metathesizing afirst alkenyl group, a second alkenyl group, and a third alkenyl group.In still other embodiments, the present disclosure providesmetathesizing a first alkenyl group, a second alkenyl group, and a firstalkynyl group. In yet further embodiments, the present disclosureprovides metathesizing a first alkenyl group, a first alkynyl group, anda second alkynyl group.

The points of unsaturation may be present in the same molecule, therebyeffecting a ring closing metathesis or intramolecular ring closing. Assuch, the single compound comprises at least the first alkenyl oralkynyl group and the second alkenyl or alkynyl group. The alkenyland/or alkynyl group may be a terminal or internal group. The singlecompound may also contain other points of unsaturation or substituentsthat do not interfere with the metathesis.

In some embodiments, the one or more compound that can undergo ametathesis is of Formula (X1)-(X5):

In these compounds, R^(A) to R^(G) are, independently, H, optionallysubstituted C₁₋₁₂alkyl, optionally substituted C₂₋₁₂alkenyl, optionallysubstituted C₂₋₁₂alkynyl, optionally substituted C₁₋₁₂haloalkyl,optionally substituted C₁₋₁₂heteroalkyl, optionally substitutedC₃₋₁₂cycloalkyl, optionally substituted aryl, optionally substitutedheteroaryl, optionally substituted heterocyclyl, OH, sulfonyl, CN, NO₂,halo, amino, C(O)H, COOH, acyl, carboxyl, amido, silyl, boryl, stannyl,or germyl. In other embodiments, R^(A) to R^(G) are, independently, H,halo (e.g., F, Cl, Br, I), OH, sulfhydryl, alkoxy, aryloxy, aralkyloxy,acyl (including alkylcarbonyl, arylcarbonyl, acyloxy (alkylcarbonyloxyand arylcarbonyloxy), alkoxycarbonyl, aryloxycarbonyl, halocarbonyl,carboxy, carboxylate), carbamoyl, mono-(alkyl)-substituted carbamoyl,di-(alkyl)-substituted carbamoyl, mono-(aryl)-substituted carbamoyl,di-(aryl)substituted, di-N-(alkyl),N-(aryl)-substituted carbamoyl,thiocarbamoyl, mono-(alkyl)-substituted thiocarbamoyl,di-(alkyl)-substituted thiocarbamoyl, mono-(aryl)substitutedthiocarbamoyl, di-(aryl)-substituted thiocarbamoyl, di-N-(alkyl),N-(aryl)-substituted thiocarbamoyl, CN, OCN, thiocyanato, formyl, C(S)H,NH₂, mono-(alkyl)-substituted amino, di-(alkyl)-substituted amino,mono-(aryl)substituted amino, di-(aryl)-substituted amino, alkylamido,arylamido, NO₂, NO, alkylthio (—S-alkyl), arylthio (—S-aryl), alkyl,alkenyl, alkynyl, aryl, or aralkyl.

The Linker is absent or may be optionally substituted C₁₋₂₀alkyl,optionally substituted C₁₋₂₀heteroalkyl, optionally substitutedC₃₋₁₂cycloalkyl, optionally substituted aryl, optionally substitutedheteroaryl, optionally substituted heterocyclyl, sulfonyl, amino,carboxyl, or amido. In some embodiments, the Linker is a size thatprovides a product having about 4 to about 10 atoms. In otherembodiments, the linker is a size that provides a product having about 5to about 8 atoms, i.e., 5 atoms, 6 atoms, 7 atoms, or 8 atoms. Thus, insome embodiments, the linker has about 3 atoms, 4 atoms, 5 atoms, or 6atoms.

In some embodiments, the compound is:

Alternatively, the points of unsaturation may be in two or moremolecules. As such a first compound contains one point of unsaturationand a second compound contains the second point of unsaturation. Thus,the metathesis is an intermolecular reaction. In some embodiments, thefirst compound comprises the first alkenyl or alkynyl group and thesecond compound comprises the second alkenyl or alkynyl group. Thealkenyl and/or alkynyl group may be a terminal or internal group. Thesingle compound may also contain other points of unsaturation orsubstituents that do not interfere with the metathesis.

In some embodiments, the first compound and second compound areindependently (X1)-(X5):

In these compounds, R^(A) to R^(G) are, independently, H, optionallysubstituted C₁₋₁₂alkyl, optionally substituted C₂₋₁₂alkenyl, optionallysubstituted C₂₋₁₂alkynyl, optionally substituted C₁₋₁₂haloalkyl,optionally substituted C₁₋₁₂heteroalkyl, optionally substitutedC₃₋₁₂cycloalkyl, optionally substituted aryl, optionally substitutedheteroaryl, optionally substituted heterocyclyl, OH, sulfonyl, CN, NO₂,halo, amino, C(O)H, COOH, acyl, carboxyl, amido, silyl, boryl, stannyl,or germyl. In other embodiments, R^(A) to R^(G) are, independently, H,halo (e.g., F, Cl, Br, I), OH, sulfhydryl, alkoxy, aryloxy, aralkyloxy,acyl (including alkylcarbonyl, arylcarbonyl, acyloxy (alkylcarbonyloxyand arylcarbonyloxy), alkoxycarbonyl, aryloxycarbonyl, halocarbonyl,carboxy, carboxylate), carbamoyl, mono-(alkyl)-substituted carbamoyl,di-(alkyl)-substituted carbamoyl, mono-(aryl)-substituted carbamoyl,di-(aryl)substituted, di-N-(alkyl),N-(aryl)-substituted carbamoyl,thiocarbamoyl, mono-(alkyl)-substituted thiocarbamoyl,di-(alkyl)-substituted thiocarbamoyl, mono-(aryl)substitutedthiocarbamoyl, di-(aryl)-substituted thiocarbamoyl, di-N-(alkyl),N-(aryl)-substituted thiocarbamoyl, CN, OCN, thiocyanato, formyl, C(S)H,NH₂, mono-(alkyl)-substituted amino, di-(alkyl)-substituted amino,mono-(aryl)substituted amino, di-(aryl)-substituted amino, alkylamido,arylamido, NO₂, NO, alkylthio (—S-alkyl), arylthio (—S-aryl), alkyl,alkenyl, alkynyl, aryl, or aralkyl.

The Linker is absent or may be optionally substituted C₁₋₂₀alkyl,optionally substituted C₁₋₂₀heteroalkyl, optionally substitutedC₃₋₁₂cycloalkyl, optionally substituted aryl, optionally substitutedheteroaryl, optionally substituted heterocyclyl, sulfonyl, amino,carboxyl, or amido. In some embodiments, the Linker is a size thatprovides a product having about 4 to about 10 atoms. In otherembodiments, the linker is a size that provides a product having about 5to about 8 atoms, i.e., 5 atoms, 6 atoms, 7 atoms, or 8 atoms. Thus, insome embodiments, the linker has about 3 atoms, 4 atoms, 5 atoms, or 6atoms.

In other embodiments, the two or more compounds are selected from among:

Metathesis Methods

As described herein, the present disclosure is directed to methods forchemical metathesis that can be performed easily, with high yields, andat ambient temperatures. The methods include the use of visible light, aruthenium metathesis catalyst and a photoredox catalyst that isactivated by the visible light. In some embodiments, these methodsinclude applying visible light to one compound comprising a firstalkenyl or alkynyl group and a second alkenyl or alkynyl group. In otherembodiments, these methods include applying visible light to a firstcompound comprising a first alkenyl or alkynyl group and a secondcompound comprising a second alkenyl or alkynyl group. The visible lightis applied to the compounds in the presence of the ruthenium metathesiscatalyst and photoredox catalyst.

The metathesis may be any type of chemical reaction that exchangeschemical bonds to result in one or more products that differ from thereactants. Thus, the metathesis may be a ring-closing metathesis,cross-metathesis, ring-opening metathesis polymerization,photolithographic olefin metathesis polymerization. In some embodiments,the methods described herein relate to ring-closing metathesis, i.e., anintramolecular metathesis. In other embodiments, the methods describedherein relate to cross-metathesis, i.e., an intermolecular metathesis.In further embodiments, the methods described herein related toring-opening metathesis polymerization. In yet other embodiments, themethods relate to photolithographic olefin metathesis polymerization.

Advantageously, the methods discussed herein may be performed at a rangeof temperatures without an adverse effect of the yield or conversion. Insome embodiments, the metathesis is performed at a temperature of about−80 to about 200° C. In further embodiments, the metathesis may beperformed at about −80° C., about −75° C., about −70° C., about −65° C.,about −60° C., about −55° C., about −50° C., about −45° C., about −40°C., about −35° C., about −30° C., about −25° C., about −20° C., about−15° C., about −10° C., about −5° C., about 0° C., about 10° C., about15° C., 20° C., about 25° C., about 30° C., about 35° C., about 40° C.,about 45° C., about 50° C., about 55° C., about 60° C., about 65° C.,about 70° C., about 75° C., about 80° C., about 85° C., about 90° C.,about 95° C., about 100° C., about 105° C., about 110° C., about 115°C., about 120° C., about 125° C., about 130° C., about 135° C., 140° C.,about 145° C., about 150° C., about 155° C., about 160° C., about 165°C., about 170° C., about 175° C., about 180° C., about 185° C., about190° C., about 195° C., or about 200° C. In other embodiments, themetathesis may be performed at a temperature at about −80 to about 180°C., about −80 to about 150° C., about −80 to about 125° C., about −80 toabout 100° C., about −80 to about 75° C., about −80 to about 50° C.,about −80 to about 25° C., about −80 to about 0° C., about −80 to about−20° C., about −30 to about 180° C., about −30 to about 150° C., about−30 to about 125° C., about −30 to about 100° C., about −30 to about 75°C., about −30 to about 50° C., about −30 to about 25° C., about −30 toabout 0° C., about −30 to about −20° C., about −10 to about 180° C.,about −10 to about 150° C., about −10 to about 125° C., about −10 toabout 100° C., about −10 to about 75° C., about −10 to about 50° C.,about −10 to about 25° C., about −10 to about 0° C., about 0 to about180° C., about 0 to about 150° C., about 0 to about 125° C., about 0 toabout 100° C., about 0 to about 75° C., about 0 to about 50° C., about 0to about 25° C., 10 to about 180° C., about 10 to about 150° C., about10 to about 125° C., about 10 to about 100° C., about 10 to about 75°C., about 10 to about 50° C., or about 10 to about 25° C. In yet otherembodiments, the metathesis is performed at room temperature. In stillfurther embodiments, the metathesis is performed at a temperature ofabout 20 to about 30° C.

The amount of the ruthenium metathesis catalyst and/or photoredoxcatalyst depends on the compound to be metathesized and product to beprepared. In some embodiments, lower amounts of the ruthenium metathesiscatalyst and/or photoredox catalyst are used. In other embodiments, itis contemplated that higher amounts of the ruthenium metathesis catalystand/or photoredox catalyst may be required. Thus, in some embodiments,the metathesis is performed using about 0.01 to about 10 mol %, based onthe mol % of the one compound or first and second compound, of theruthenium metathesis catalyst. In other embodiments, the metathesis isperformed using about 0.05 to about 10 mol %, about 1 to about 10 mol %,about 1.5 to about 10 mol %, about 2 to about 10 mol %, about 2.5 toabout 10 mol %, about 3 to about 10 mol %, about 3.5 to about 10 mol %,about 4 to about 10 mol %, about 4.5 to about 10 mol %, about 5 to about10 mol %, about 5.5 to about 10 mol %, about 6 to about 10 mol %, about6.5 to about 10 mol %, about 7 to about 10 mol %, about 7.5 to about 10mol %, about 8 to about 10 mol %, about 8.5 to about 10 mol %, about 9to about 10 mol %, about 0.01 to about 9 mol %, about 0.01 to about 8mol %, about 0.01 to about 7 mol %, about 0.01 to about 6 mol %, about0.01 to about 5 mol %, about 0.01 to about 4 mol %, about 0.01 to about3 mol %, about 0.01 to about 2 mol %, about 0.01 to about 1 mol %, about2 to about 7.5 mol %, about 2.5 to about 7.5 mol %, about 5 to about 7mol %, or about 5 to about 10 mol %, based on the mol % of the onecompound or first and second compound, of the ruthenium metathesiscatalyst. In further embodiments, the metathesis is performed usingabout 2 to about 7.5 mol %, based on the mol % of the one compound orfirst and second compound, of the ruthenium metathesis catalyst. Instill other embodiments, the metathesis is performed using about 5 mol%, based on the mol % of the one compound or first and second compound,of the ruthenium metathesis catalyst.

Thus, in some embodiments, the metathesis is performed using about 0.05to about 10 mol %, based on the mol % weight of the one compound orfirst and second compound, of the photoredox catalyst. In otherembodiments, the metathesis is performed using about 1 to about 10 mol%, about 1.5 to about 10 mol %, about 2 to about 10 mol %, about 2.5 toabout 10 mol %, about 3 to about 10 mol %, about 3.5 to about 10 mol %,about 4 to about 10 mol %, about 4.5 to about 10 mol %, about 5 to about10 mol %, about 5.5 to about 10 mol %, about 6 to about 10 mol %, about6.5 to about 10 mol %, about 7 to about 10 mol %, about 7.5 to about 10mol %, about 8 to about 10 mol %, about 8.5 to about 10 mol %, about 9to about 10 mol %, about 0.05 to about 9 mol %, about 0.05 to about 8mol %, about 0.05 to about 7 mol %, about 0.05 to about 6 mol %, about0.05 to about 5 mol %, about 0.05 to about 4 mol %, about 0.05 to about3 mol %, about 0.05 to about 2 mol %, about 0.05 to about 1 mol %, about2 to about 7.5 mol %, about 2.5 to about 7.5 mol %, about 5 to about 7mol %, or about 5 to about 10 mol %, based on the mol % of the onecompound or first and second compound, of the photoredox catalyst. Infurther embodiments, the metathesis is performed using about 2 to about7.5 mol %, based on the mol % of the one compound or first and secondcompound, of the photoredox catalyst. In still other embodiments, themetathesis is performed using about 7.5 mol %, based on the mol % of theone compound or first and second compound, of the photoredox catalyst.

The inventors also found that the concentration of the one or morecompounds containing the points of unsaturation can be adjusted tooptimize the metathesis. In some embodiments, the concentration of theone compound or first and second compound, all containing points ofunsaturation, is about 0.01 to about 5M. In other embodiments, theconcentration is about 0.01 to about 4.5M, about 0.01 to about 4M, about0.01 to about 3.5M, about 0.01 to about 3M, about 0.01 to about 2.5M,about 0.01 to about 2M, about 0.01 to about 1.5M, about 0.01 to about1M, about 0.01 to about 0.05M, about 0.5M to about 5M, about 0.1 toabout 1M, about 0.1 to about 0.8M, about 0.1 to about 0.75M, about 0.1to about 0.5M, about 0.1 to about 0.4M, about 0.1 to about 0.3M, about0.1 to about 0.2M, about 1 to about 5M, about 1.5 to about 5M, about 2to about 5M, about 2.5 to about 5M, about 3 to about 5M, about 3.5 toabout 5M, about 4 to about 5M, or about 4.5 to about 5M. In furtherembodiments, the concentration is about 0.01 to about 0.5 M. In yetother embodiments, the concentration is about 0.1 to about 0.3 M.

The metathesis is performed for a period of time as determined by thoseskilled in the art depending on the ruthenium catalyst, photoredoxcatalyst, temperature, and one or more compounds to be metathesized. Thereaction time can be varied as needed to control the thickness of themetathesized compound, among others. Thus, shorter periods of times mayresult in thinner polymers, whereas longer periods of time may result inthicker polymers. In some embodiments, the metathesis is performed forat least about 10 seconds. In other embodiments, the metathesis isperformed for at least about 1 minute. In further embodiments, themetathesis is performed for at least about 2 minutes, 3 minutes, 4minutes, 5 minutes, 10 minutes, 30 minutes, 60 minutes, 2 hours, 3hours, 4 hours, 5 hours, 6 hours, 12 hours, or 24 hours, or longer.

Spatial Control Methods

In addition to the fact that the metatheses described herein may beperformed with high yields and conversions, optionally at ambientconditions when needed, the inventors found that they could be spatiallycontrolled. As such, methods for spatially controlling a metathesis alsoare provided by the disclosure, as are methods for preparing polymericmaterials or patterns, and patterning surfaces on a micro scale asdescribed below.

The term “micro scale” as used herein refers to patterned polymershaving a size of about 1 mm or less. The size may be in any direction ofthe patter, i.e., width, length or depth. In some embodiments, microscale refers to a size of about 1 nm to about 1 mm. In otherembodiments, micro scale refers to a size of about 1 nm to about 1 Infurther embodiments, micro scale refers to a size of about 1 μm to about1 mm. In still other embodiments, micro scale refers to a size of about10 to about 100 μm, about 20 to about 100 μm, about 30 to about 100 μm,about 40 to about 100 μm, about 50 to about 100 μm, about 60 to about100 μm, about 70 to about 100 μm, about 80 to about 100 μm, about 90 toabout 100 μm, about 10 to about 90 μm, about 10 to about 80 μm, about 10to about 80 μm, about 10 to about 70 μm, about 10 to about 60 μm, about10 to about 50 μm, about 10 to about 40 μm, about 10 to about 30 μm,about 10 to about 20 μm, about 20 to about 90 μm, about 20 to about 80μm, about 20 to about 70 μm, about 20 to about 60 μm, about 20 to about50 μm, about 20 to about 40 μm, about 20 to about 30 μm, about 30 toabout 90 μm, about 30 to about 80 μm, about 30 to about 70 μm, about 30to about 60 μm, about 30 to about 60 μm, about 30 to about 50 μm, about30 to about 40 μm, about 40 to about 90 μm, about 30 to about 80 μm,about 30 to about 70 μm, about 30 to about 60 μm, about 30 to about 50μm, about 30 to about 40 μm, about 40 to about 90 μm, about 40 to about80 μm, about 40 to about 70 μm, about 40 to about 60 μm, about 40 toabout 50 μm, about 50 to about 90 μm, about 50 to about 80 μm, about 50to about 70 μm, about 50 to about 60 μm, about 60 to about 90 μm, about60 to about 80 μm, about 60 to about 70 μm, about 70 to about 90 μm,about 70 to about 80 μm, or about 80 to about 90 μm.

Methods of spatially controlling a metathesis comprise forming a mixtureof a ruthenium metathesis catalyst, a photoredox catalyst, and one ormore compounds susceptible to metathesis and applying visible light toone or more regions of the mixture. By doing so, the methods provide oneor more metathesized regions and one or more unmetathesized regions.

The mixture may be formed or added to a substrate that contains themixture. In some embodiments, the substrate is a glass, plastic, anorganic surface including a metal such as gold, or iron, cloth, wood,silicon, diamond, graphite, charcoal, metal organic framework, amongothers. In some embodiments, the substrate is a petri dish. In otherembodiments, the substrate is a wafer, such as a silicon wafer. As such,the substrate does not participate in the metathesis or otherwise formany bonds with the one or more compounds, ruthenium metathesis catalyst,photoredox catalyst, or product formed therefrom.

Thus, in certain embodiments, the mixture may be disposed on thesubstrate prior to metathesis. In further embodiments, the mixture isdisposed on a substrate that does not participate in the metathesis.

The disclosure also envisions embodiments wherein substrate isfunctionalized with the one or more compounds susceptible to metathesis,ruthenium metathesis catalyst, photoredox catalyst, or combinationsthereof. By doing so, the substrate is linked to a metathesized region.In some embodiments, the substrate is functionalized with the one ormore compounds susceptible to metathesis. In other embodiments, thesubstrate is pre-functionalized with the one or more compound beforeadding the photoredox catalyst or ruthenium metathesis catalyst. Infurther embodiments, the substrate is functionalized with the photoredoxcatalyst. In yet other embodiments, the substrate is functionalized withthe ruthenium metathesis catalyst. As but one example, the presentdisclosure provides methods that comprise applying visible light to aruthenium metathesis catalyst, a photoredox catalyst, and one or morecompounds susceptible to metathesis, the applying being performed so asto give rise to one or more metathesized regions, at least one of theruthenium metathesis catalyst and the photoredox catalyst (or even bothof the foregoing) being linked to a substrate, the substrate optionallybeing stationary. The visible light can be applied in a predeterminedpattern. The visible light can also be applied from two or more sources.

The visible light may be applied using any light source known in theart. On some embodiments, the visible light is applied using a highresolution light source. The term “high resolution” as used hereinrefers to light that is delivered to a specific location on a substrate.In some embodiments, the high resolution light source is a laser. Inother embodiments, the high resolution light source is a fine beam oflight.

In order to spatially control the metathesis, the regions that are notto be metathesized, i.e., the unmetathesized regions, are covered with aphotomask. By doing so, the light penetrates the mask in intendedlocations as determined by the shape and placement of the mask. Theterms “mask” and “photomask” as used herein are interchangeable andrefer to an object that physically covers regions of the compoundssusceptible to metathesis. Desirably, the mask is substantially opaqueto visible light. In some embodiments, the mask is black in color ormade of a material that reflects visible light. In other embodiments,the mask is black paper, black plastic, a metal sheet, or a metal foil.The mask may also have one or more openings whereby visible light maypass through. By doing so, those openings permit the visible light toonly be applied to those regions of the mixture that are intended tometathesize. As the final product, the mixture will containunmetathesized and metathesized regions.

The disclosure also provides steps for recovering only thosemetathesized regions. In doing so, the unmetathesized regions may beremoved by rinsing with a solvent. In some embodiments, the solvent isadded to the mixture and thereby removed to provide the metathesizedregion. The solvent selected desirably is effect to only solubilize theunmetathesized regions, and not the metathesized regions. One skilled inthe art would understand how long the rinsing should be performed andhow best to remove the solvent after rinsing.

A further embodiment of the present disclosure is a method of exertingspatial control over metathesis comprising: (a) providing a reactionmixture of a latent metathesis catalyst, a photocatalyst, and asubstrate; and (b) applying visible light to selected areas of thereaction mixture; wherein the selected areas of the reaction mixture areselected by: (i) macroscopic or microscopic photomask; or (ii) highresolution light source. In some embodiments, the reaction mixture isprovided on a support surface. In certain embodiments, the supportsurface is a pre-functionalized support surface.

Another embodiment of the present disclosure is a method for visiblelight controlled olefin metathesis, comprising: (a) providing a reactionmixture of a latent metathesis catalyst, a photocatalyst, and asubstrate; and (b) applying visible light to the reaction mixture for adesired time. In some embodiments, the olefin metathesis is selectedfrom ring-closing metathesis (RCM), cross-metathesis (CM), andring-opening metathesis polymerization (ROMP). In some embodiments, step(b) of the method disclosed above is carried out at room temperature.

The present disclosure further provides compositions and processes asdisclosed or depicted in the Appendix attached hereto, and/or kitscontaining such compositions or for carrying out such processes.

The embodiments described in this disclosure can be combined in variousways. Any aspect or feature that is described for one embodiment can beincorporated into any other embodiment mentioned in this disclosure.While various novel features of the inventive principles have beenshown, described and pointed out as applied to particular embodimentsthereof, it should be understood that various omissions andsubstitutions and changes may be made by those skilled in the artwithout departing from the spirit of this disclosure. Those skilled inthe art will appreciate that the inventive principles can be practicedin other than the described embodiments, which are presented forpurposes of illustration and not limitation.

The following listing of aspects is intended to complement, rather thandisplace or supersede, the previous descriptions.

Aspects

Aspect 1: A composition for olefin metathesis comprising a latentmetathesis catalyst and a photocatalyst, wherein the olefin metathesisis controlled by visible light irradiation.

Aspect 2: The composition of aspect 1, wherein the latent metathesiscatalyst is a bis(NHC)— ruthenium complex.

Aspect 3: The composition of aspect 2, wherein the bis(NHC)-rutheniumcomplex is selected from IMes₂RuCl₂CHPh and SIMes₂RuCl₂CHPh.

Aspect 4: The composition of aspect 2, wherein the bis(NHC)-rutheniumcomplex is IMes₂RuCl₂CHPh.

Aspect 5: The composition of aspect 1, wherein the photocatalyst is ahighly oxidizing photocatalyst.

Aspect 6: The composition of aspect 1, wherein the photocatalyst isselected from acridinium and pyrylium derivatives.

Aspect 7: The composition of aspect 1, wherein the photocatalyst is2,4,6-tri-phenylpyrylium tetrafluoroborate (TPPT).

Aspect 8: A composition comprising IMes₂RuCl₂CHPh and2,4,6-tri-phenylpyrylium tetrafluoroborate (TPPT).

Aspect 9: A method for visible light controlled olefin metathesis,comprising: providing a reaction mixture of a latent metathesiscatalyst, a photocatalyst, and a substrate; and applying visible lightto the reaction mixture for a desired time.

Aspect 10: The method of aspect 9, wherein the olefin metathesis isselected from ring-closing metathesis (RCM), cross-metathesis (CM), andring-opening metathesis polymerization (ROMP).

Aspect 11: The method of aspect 9, wherein the latent metathesiscatalyst is a bis(NHC)— ruthenium complex and the photocatalyst is ahighly oxidizing photocatalyst.

Aspect 12: The method of aspect 9, wherein step (b) is carried out atroom temperature.

Aspect 13: The method of aspect 11, wherein the bis(NHC)-rutheniumcomplex is selected from IMes₂RuCl₂CHPh and SIMes₂RuCl₂CHPh, and thephotocatalyst is selected from acridinium and pyrylium derivatives.

Aspect 14: The method of aspect 9, wherein the latent metathesiscatalyst is IMes₂RuCl₂CHPh and the photocatalyst is2,4,6-tri-phenylpyrylium tetrafluoroborate (TPPT).

Aspect 15: A method of exerting spatial control over metathesiscomprising: providing a reaction mixture of a latent metathesiscatalyst, a photocatalyst, and a substrate; and applying visible lightto selected areas of the reaction mixture; wherein the selected areas ofthe reaction mixture are selected by: (i) macroscopic or microscopicphotomask; or (ii) high resolution light source.

Aspect 16: The method of aspect 15, wherein the reaction mixture isprovided on a support surface.

Aspect 17: The method of aspect 16, wherein the support surface is apre-functionalized support surface.

Aspect 18: The method of aspect 15, wherein the latent metathesiscatalyst is a bis(NHC)— ruthenium complex.

Aspect 19: The method of aspect 18, wherein the bis(NHC)-rutheniumcomplex is selected from IMes₂RuCl₂CHPh and SIMes₂RuCl₂CHPh.

Aspect 20: The method of aspect 15, wherein the photocatalyst is ahighly oxidizing photocatalyst.

Aspect 21: The method of aspect 15, wherein the photocatalyst isselected from acridinium and pyrylium derivatives.

Aspect 22: The method of aspect 15, wherein the photocatalyst is2,4,6-tri-phenylpyrylium tetrafluoroborate (TPPT).

Aspect 23: The method of aspect 15, wherein the latent metathesiscatalyst is IMes₂RuCl₂CHPh and the photocatalyst is2,4,6-tri-phenylpyrylium tetrafluoroborate (TPPT).

Aspect 24: A composition or process as disclosed or depicted in Appendix1.

The following Examples are provided to illustrate some of the conceptsdescribed within this disclosure. While each Example is considered toprovide specific individual embodiments of composition, methods ofpreparation and use, none of the Examples should be considered to limitthe more general embodiments described herein.

In the following examples, efforts have been made to ensure accuracywith respect to numbers used (e.g. amounts, temperature, etc.) but someexperimental error and deviation should be accounted for. Unlessindicated otherwise, temperature is in degrees C., pressure is at ornear atmospheric.

EXAMPLES Example 1

Olefin metathesis is one of the most attractive and powerful tools forthe creation of carbon-carbon π bonds, finding numerous applications insynthetic chemistry, fine chemical synthesis and materials science. See,Grela, Olefin Metathesis: Theory and Practice; Wiley: Hoboken, N.J.,2014; Grubbs, Handbook of Metathesis, 2nd ed.; Wiley-VHC: Weinheim,2015; Trnka, Acc. Chem. Res. 2001, 34, 18-29; Hoveyda, Nature 2007, 450,243-250. Ogba, Chem. Soc. Rev. 2018, 47, 4510-4544. Katz, Angew. Chem.Int. Ed. 2005, 44, 3010-3019; Higman, Angew. Chem. Int. Ed. 2016, 55,3552-3565. While most synthetic efforts have been devoted to thedevelopment of ever-more efficient catalysts, increased attention hasbeen paid to the development of catalysts that can beactivated/deactivated on demand. See, Blanco, Chem. Soc. Rev. 2015, 44,5341-5370; Choudhury, Tetrahedron Lett. 2018, 59, 487-495. Such latentcatalysts are dormant species under ambient conditions and require anexternal stimulus to become active. Increased control on reactions iscrucial not only from an understanding viewpoint but also forapplications in materials science for the production of new well-definedmaterials. See, Leibfarth, Angew. Chem. Int. Ed. 2013, 52, 199-210;Teator, Chem. Rev. 2016, 116, 1969-1992; Ogawa, Synlett 2016, 27,203-214; Teator, J. Polym. Sci. Pol. Chem. 2017, 55, 2949-2960. Variousstimuli have been exploited to achieve such control in metathesisreactions, including heat, light, ultrasound, acid and redox switches.See, Szadkowska, Curr. Org. Chem. 2008, 12, 1631-1647; Monsaert, Chem.Soc. Rev. 2009, 38, 3360-3372; Vidaysky, J. Org. Chem. 2010, 6,1106-1119; Eivgi, Synthesis 2018, 50, 49-63. Light is arguably the mostconvenient and attractive stimulus since it is non-invasive, can beeasily manipulated and provides the opportunity for high temporal andspatial resolution (FIG. 1). See, Stoll, Angew. Chem. Int. Ed. 2010, 49,5054-5075; Neilson, ACS Catal. 2013, 3, 1874-1885; Gostl, Chem. Soc.Rev. 2014, 43, 1982-1996. As a consequence, several recent reports havedescribed light-promoted olefin metathesis. See, Wang, Angew. Chem. Int.Ed. 2008, 47, 3267-3270; Wang, Chem. Eur. J. 2010, 16, 12928-12934;Keitz, J. Am. Chem. Soc. 2009, 131, 2038-2039; Khalimon, Organometallics2012, 31, 5634-5637; Ben-Asuly, Organometallics 2009, 28, 4652-4655;Levin, Angew. Chem. Int. Ed. 2015, 54, 12384-12388; Sutar, Angew. Chem.Int. Ed. 2016, 55, 764-767; Teator, Organometallics 2017, 36, 490-497.While these have been important developments, they are dominated by UVlight with most reports describing activation rather than gating controlof alkene metathesis.

We considered that the merger of olefin metathesis with photoredoxcatalysis could lead to visible light control of alkene metathesis. See,Prier, Chem. Rev. 2013, 113, 5322-5363; Tellis, Acc. Chem. Res. 2016,49, 1429-1439; Romero, Chem. Rev. 2016, 116, 10075-10166; Skubi, Chem.Rev. 2016, 116, 10035-10074. Visible light photoredox catalysis hasalready proven successful for metal-free olefin metathesispolymerization via a radical mechanism. See, Ogawa, J. Am. Chem. Soc.2015, 137, 1400-1403; Goetz, J. Am. Chem. Soc. 2015, 137, 7572-7575;Goetz, ACS Macro Lett. 2016, 5, 579-582. In particular, excitation ofthe appropriate photocatalyst by visible-light irradiation should permitthe activation of a latent metathesis catalyst, most probably byinducing ligand dissociation, and therefore lead to the development ofan on-demand metathesis system. Importantly, the use of visible light ismore convenient than UV light while still providing high levels oftemporal and spatial resolution. See, Ruhl, J. Am. Chem. Soc. 2015, 138,15527-15530; Ravetz, ACS Catal. 2018, 8, 5323-5327; Ravetz, ACS Catal.2019, 9, 200-204. Overall, the development of such a system would opennew perspectives in photolithography and in materials science for thedesign of new materials, as already illustrated by the impact of recentwork reported for photo-controlled, living radical polymerizations. See,Bratton, Polym. Adv. Technol. 2006, 17, 94-103; Madou, Fundamentals ofMicrofabrication and Nanotechnology, 3rd ed., CRC Press: Boca Raton,Fla., 2011; ISBN 9780849331800; (c) Xu, Polym. J. 2018, 50, 45-55;Harris, Adv. Mater. 2005, 17, 39-42; Weitekamp, J. Am. Chem. Soc. 2013,135, 16817-16820; Teator, Chem. Rev. 2016, 116, 1969-1992; Chen, Chem.Rev. 2016, 116, 10167-10211; Fors, Angew. Chem. Int. Ed. 2012, 51,8850-8853; Anastasaki, J. Am. Chem. Soc. 2014, 136, 1141-1149; Treat, J.Am. Chem. Soc. 2014, 136, 16096-16101; Pan, J. Am. Chem. Soc. 2015, 137,15430-15433.

At the outset of these studies, we needed a ruthenium-based complex thatis inactive at ambient temperature, and identified bis-NHC ligated Rucomplexes first introduced by Herrmann. See, Weskamp, Chem. Int. Ed.1998, 37, 2490-2492. When substituted with aromatic groups on thenitrogen atoms, these catalysts lack activity for metathesis at roomtemperature, most probably because of the difficult dissociation of oneNHC ligand to generate the corresponding 14-electron active catalyst.See, Trnka, J. Am. Chem. Soc. 2003, 125, 2546-2558. At highertemperatures, the activity of these catalysts is restored. In thisregard, we surmised that the NHC dissociation event could be promoted atroom temperature by using photoredox catalysis. A carefully chosenphotocatalyst should be capable, after excitation upon irradiation withvisible light, of activating these catalysts and therefore toggling theminto their corresponding active species after dissociation of one NHC(FIG. 2).

To test our hypothesis, we first evaluated the benchmark ring closingmetathesis (RCM) of diethyl diallylmalonate using RuCl₂(CHPh)(IMes)₂ andRuCl₂(CHPh)(SIMes)₂, previously reported by Fogg and Grubbs, in thepresence of different photocatalysts under visible-light irradiation.See, Trnka cited above and Conrad, Organometallics 2003, 22, 1986-1988.After screening several photocatalysts and reaction conditions (seeExample 2 for further details), we found that a combination ofRuCl₂(CHPh)(IMes)₂ (Ru₁) and 2,4,6-triphenylpyrylium tetrafluoroborate(TPPT) as photocatalyst gives the desired product in 87% yield after 4 hof irradiation under blue LEDs at room temperature (Table 1, entry 9).While screening photocatalysts, we observed that only highly oxidizingones such as acridinium and pyrylium derivatives provide some reactivity(entries 6-8), while no product is observed when switching to lessoxidizing photocatalysts (entries 1-5). This is consistent with anactivation mode involving oxidation of the Ru catalyst followed bydissociation of one NHC to generate the catalytically active speciesforming the corresponding radical cation. See, Eelman, Angew. Chem. Int.Ed. 2008, 47, 303-306; and Bailey, ACS Catal. 2016, 6, 4962-4971. Weindeed note that Ru1 has two distinct oxidation events as identified bycyclic voltammetry, with the first occurring at +0.44 V, likelycorresponding to the generation of the radical cation by ametal-centered oxidation (see Example 2). While all photoredox catalystsshould allow oxidation to the radical cation, the dissociation eventmight be caused by a second oxidation occurring at one NHC ligand thatwould only be promoted by highly oxidizing photocatalysts and explainthat traditional Ir and Ru photocatalysts are not effective (see table1, entries 1-5). See, Ramnial, Chem. Commun. 2004, 1054-1055.Importantly, no reaction is observed in the absence of ruthenium, lightor photocatalyst (entries 10-12). The lack of reactivity under lightwithout photocatalyst also rules out a mechanism solely based onphoto-induced dissociation of one NHC ligand and highlights theimportance of the photoredox system. Finally, the use ofRuCl₂(CHPh)(SIMes)₂ (Ru₂) delivers similar reactivity (entry 13).However, background reactivity is observed in the absence of light andphotocatalyst (entry 14), indicating that dissociation of one NHChappens slowly at ambient temperature. RuCl₂(CHPh)(IMes)₂ (Ru1) waschosen as it displays optimal latent behavior.

TABLE 1 Reaction optimization and scope of RCM, CM, and ROCM reactions.(1) Reaction Optimization

  Ru(bpz)₃(PF₆)₂ E_(ox)* Entry Conditions (V vs. SCE) Yield^([b]) (%)  1Ir(ppy)₃ 0.31  0  2 [Ir(ppy)₂(dtbbpy)]PF₆ 0.66  0  3 Ru(bpy)₃Cl₂ 0.77  0 4 [Ir(dF—CF₃ppy)₂(dtbbpy)]PF₆ 1.21  0  5 Ru(bpz)₃Cl₂ 1.45  0  6MesAcrPh 2.12 33  7 MesAcrMe 2.18 16  8 TPPT 2.66 84  9 Ru₁ (2 mol %),TPPT (3 mol %), 4 h — 87 10 No Ru₁ —  0 11 No light —  0 12 Nophotocatalyst —  0 13 Ru₂ instead of Ru₁ — 75 14 Ru₂, no light, nophotocatalyst — 15 Ru(bpz)₃(PF₆)₂ 17 (b) Scope of RCM reactions^([c])

(c) Scope of CM and ROCM reactions^([c])

60%^([d, e])

70%^([d, e])

46%^([d, e])

51%^([d, f]) ^([a])All optimization reactions were conducted on a 0.1mmol scale, ^([b])Determined by ¹H NMR spectroscopy using1,2-dibromoethane as an internal standard. ^([c])Conditions: substrate(0.2 mmol), RuCl₂(CHPh)(IMes)₂ (2 mol %), TPPT (3 mol %), CH2Cl₂ (0.2M),rt, blue LEDs, 4 h. ^([d])4 mol % of TPPT. ^([e])Left substrate (0.2mmol), right substrate (0.4 mmol). ^([f])Left substrate (0.2 mmol),right substrate (0.6 mmol). ^([g])For additional samples, see Example 2.

With an efficient system in hand, we first explored its ability topromote different types of metathesis reactions. While standardmetathesis reactions can be readily promoted using this photoredoxcatalytic system, as illustrated with representative examples in Table 1and Example 2, we were more interested in interrogating ring-openingmetathesis polymerization (ROMP) applications. To this end, severalmonomers such as norbornene derivatives 1-8,11, norbornadiene9,1,5-cyclooctadiene 10 and dicyclopentadiene 12 could be readilypolymerized within 1 h under blue LED irradiation in the presence ofRuCl₂(CHPh)(IMes)₂ and TPPT (Table 2).

TABLE 2 Scope of ROMP reactions. Conversion^([b]) Theo. M_(n) Exp. M_(n)^([c]) Entry Monomer (%) (kDa) (kDa) Ð^([c])  1

>95 18.8 99.6 1.88  2

>95 66.9 215.2 1.66  3

>95 48.0 327.4 1.63  4

>95 47.7 424.8 1.84  5

 6

40-60  7

65  8

 9

99 14.4 10

99 11

12^([d])

99 13

>80 66.9 214.2 1.67 14

15

16

17

18

19

20

21

22

>80 26.8 48.1 1.32 23

24

25

99 5 ^([a])Conditions: monomer (0.2 mmol), RuCl₂(CHPh)(IMes)₂ (0.5 mol%), TPPT (1 mol %), CD₂Cl₂ (0.2M), rt, blue LEDs, 1 h. ^([b])Determinedby ¹H NMR spectroscopy using mesitylene as internal standard.^([c])Determined by GPC. ^([d])Using IMes₂RuCl₂CHPh (0.01 mol %), TPPT(0.05 mol %) for 15 min under blue LEDs.

Molecular weights (Mn) obtained after polymerization of monomers 1-4 aresignificantly higher than the expected values which suggests thatpolymerization is faster than catalyst initiation. Dispersities werefound in the range of 1.63 to 1.88. Monomers 5-10 are also smoothlypolymerized within an hour of irradiation but lead to insolublepolymers, which precludes GPC analysis. Finally, cross-linking monomers11 and 12 could also be efficiently polymerized to afford completegelation within an hour, the latter only requiring 0.01 mol % of Ru1,0.05 mol % of TPPT and 15 minutes of irradiation. Importantly, thelatency is successfully maintained with dicyclopentadiene 12 since, inthe absence of light, less than 5% polymerization is observed after 24 h(5% after 3 days, 9% after a week). When stopped after 90 seconds underlight, 16% polymerization is observed. The rate of polymerization undervisible light can therefore be estimated to be 12,000 times faster thanin the dark.

Further experiments were conducted to examine the influence of light andto probe our ability to exert temporal and spatial controls over thereaction. First, temporal control was evaluated by conducting on/offexperiments with alternating periods of irradiation and darkness for thering closing metathesis of diethyl diallylmalonate. The ability to exerttemporal control over a reaction is of great interest for the design oforthogonal multicomponent reactions, as well as for the development ofnew systems designed to produce new highly functionalized materials. Ascan be seen in FIGS. 3 and 4, temporal control can be achieved sincemaximal reactivity was obtained during irradiation whereas darkness onlyafforded minimal increases in yields (from 0 to 3%).

A series of experiments lead us to suggest the following mechanism forthe on/off behavior enabled by photoredox catalysis and lightirradiation. See, Ogawa cited above. It is commonly accepted that Rucatalysts mediate olefin metathesis via a coordinatively unsaturatedRu(II) intermediate such as II (FIGS. 3 and 4). Given that only highlyoxidizing excited state photocatalysts provide appreciable yield (Table1), we propose that ligand loss occurs at ambient temperature from anoxidized Ru intermediate, potentially at the IMes moiety to give activemetathesis catalyst II and reduced pyrylium V as well as VI. The lattertwo can combine to form VII, analogous to adducts reported lackingsubstitution at the 4 position. Release of the IMes provides a pool offree ligand which can coordinate IV and arrest catalysis. See, Antoni,J. Am. Chem. Soc. 2018, 140, 14823-14835; and Branchi, J. Org. Chem.2004, 69, 8874-8885.

We also interrogated our ability to exert spatial control overmetathesis with this system, due to the potential applications inmaterials science with polymer patterning, 3D printing andphotolithography. In this regard, the development of a system controlledby visible light appears especially attractive and convenient. To thisend, dicyclopentadiene 12, and some other monomers, were firstirradiated with visible light (blue Kessil lamp, 40 W) in the presenceof RuCl₂(CHPh)(IMes)₂ and TPPT through different photomasks in order toproduce macroscopic polymers with controlled geometric patterns. Similarpatterning could be obtained with: norbornadiene 9,1,5-cyclooctadiene 10and 5-ethylidene-2-norbornene 11. Removal of the masks and unreactedmonomers nicely affords the corresponding patterned polymers in shortirradiation times (15-60 minutes) and with minimal bleeding in theunexposed areas (FIGS. 5-9). The amount of monomer consumed that is notpresent in the final patterned polymer was estimated at 7% by analysisof the wash using an external reference. Interestingly, the thickness ofthese patterned polymers can be easily controlled by tuning theirradiation time (see Example 2). Finally, an important feature of thissystem is its practicality and user-friendliness. While the excitedstate TPPT* is modestly sensitive to oxygen, the photomask patterningexperiments can be performed with minimal precautions of placing themonomer/catalyst mixture under a blanket of inert gas.

Higher resolutions are required in order to apply thisvisible-light-controlled system for applications in PhotoLithographicOlefin Metathesis Polymerization (PLOMP). While most photolithographictechniques are based on the use of high resolution photomasks, anattractive alternative is the use of high resolution light sources, suchas lasers, which should provide a straightforward way to reach pinpointresolution and find new applications in photolithography. See, Rühe, ACSNano 2017, 11, 8537-8541. As proof of concept, we could successfullyinduce similar patterning from dicyclopentadiene solutions using asimple blue laser pointer (200 mV). In these cases, the patterns aredirectly and conveniently “drawn” from the bulk solution in a fewminutes, either manually (FIGS. 7A and 7B) or using an orbital shakerproviding constant movement (FIG. 7C).

The two afore-described techniques allow the convenient fabrication ofmacroscopic patterned polymers through spatially-resolved ROMP promotedby visible light and without the need for grafting of the monomers. Asfor microscopic patterning, we also demonstrate the efficiency of oursystem for PLOMP applications. Although photolithography is now acommonly used technique in microfabrication, such systems based onolefin metathesis are still rare. To this end, 1 cm×1 cm silicon waferswere first pre-functionalized with a norbornene unit to ensure graftingof the growing polymer onto the surface. See, Harris and Weitekamp citedabove. Those pre-functionalized silicon wafers were then used as supportto perform the spatially-resolved polymerization of norbornadiene on amicroscale by simply irradiating a solution of the monomer,RuCl₂(CHPh)(IMes)₂ and TPPT in dichloromethane with a regular blue LEDlight bulb (blue Kessil lamp, 40 W) through high resolution photomasks(FIG. 9A).

Example 2

General Information.

All reactions were carried out in oven-dried glassware under an argon ornitrogen atmosphere employing standard techniques in handlingair-sensitive materials.

All solvents were reagent grade. Dichloromethane (anhydrous, >99.8%),hexane (anhydrous, 95%), pyridine (anhydrous, 99.8%) and toluene(anhydrous, 99.8%) were purchased from Sigma-Aldrich and used assupplied. Benzene (anhydrous, 99.8%) was purchased from Merck and usedas supplied. Grubbs 1st and 2nd generation catalysts and SIMes werepurchased from Sigma Aldrich and used as supplied. IMes was purchasedfrom TCI Chemicals and used as supplied. All photocatalysts used wereeither synthesized by known methods or bought from commercial sources.2,4,6-Triphenylpyrylium tetrafluoroborate in particular was purchasedfrom Sigma Aldrich and used as supplied.Trichloro(5-norbornen-2-yl)silane was synthesized based on a reportedprocedure.1 All other reagents were used as supplied.

All photochemical reactions were performed in 1-dram vials fitted withTeflon caps under irradiation with two blue PR160-440 nm Kessil 40 W LEDlamps. Reactions were magnetically stirred and monitored by thin layerchromatography using SiliCycle® 250 μm 60 Å plates. Flash chromatographywas performed with silica gel 60 Å (particle size 40-63 μm) supplied bySiliCycle®. Yields refer to chromatographically and spectroscopicallypure compounds unless otherwise stated.

All polymer patterning experiments were performed in BRAND® petri dishes(glass, 40 mm×12 mm or 80 mm×15 mm) purchased from Sigma Aldrich. AUKing ZQ-J33 200 mW 532 nm & 450 nm double light 5 in 1 USB laserpointer was purchased from www.laserpointerpro.com. Silicon wafers (4″,2850 Å oxide layer, resistivity 0.001-.005 ohm-cm, p-type, orientation<100>) were purchased from NOVA Electronic Materials (Item #H539626-OX).Masks were drawn in CAD software and printed by CAD/ART Services, Inc.(Brandon, Oreg.).

Proton NMR spectra were recorded using an internal deuterium lock atambient temperature on a Bruker 500 MHz spectrometer. Internal referenceof δ_(H) 7.26 was used for CDCl3. Data are presented as follows:chemical shift (in ppm on the δ scale relative to δ_(TMS)=0),multiplicity (s=singlet, d=doublet, t=triplet, q=quartet, m=multiplet,br.=broad, app.=apparent), coupling constant (J/Hz) and integration.Resonances that are either partially or fully obscured are denotedobscured (obs.). Carbon-13 NMR spectra were recorded at 125 MHz usingCDCl₃ (δ_(C) 77.16) as internal reference. Fluorine-19 NMR spectra wererecorder at 470 MHz using CF₃CH₂OH (δ_(F)—77.59) as external reference.

High-resolution mass spectra were obtained on a Waters XEVO G2XSQToFmass spectrometer. Infrared spectra were recorded on a Perkin ElmerSpectrum Two FT-IR Spectrometer. GPC analysis were performed on anAgilent 1260 Infinity GPC using 2×300 mm Agilent PLGel Mixed-D columnsand G1362A RI or G1365D multiwavelength detectors, calibrated againstpolystyrene standards.

All cyclic voltammetry studies were performed on a CH instruments Model1232B potentiostat using an EDAQ 1-mm disk glassy carbon workingelectrode in conjunction with an EDAQ Ag/AgCl reference electrode and aplatinum wire from VWR as counter electrode. All experiments wereperformed in anhydrous dichloromethane (RuCl₂(CHPh)(IMes)₂ andRuCl₂(CHPh)(SIMes)₂) or tetrahydrofuran (free IMes and free SIMes) at 5mM using tetrabutylammonium hexafluorophosphate (0.1 M) as electrolyte.The scan rate was set at 100 mV/s.

Plasma treatments were conducted using a PE-50 Compact Benchtop PlasmaCleaning System manufactured by Plasma Etch, Inc. Micrographs of thepatterned silicon wafers were recorded on a Nikon Eclipse LV150Nmicroscope. Step heights were measured by imaging 10 μm sections (0.5Hz, 256 samples/line) on a Bruker Dimension Icon AFM using aScanasyst-Air probe in Scanasyst mode.

A. Synthesis of RuCl₂(CHPh)(IMes)₂

(i) Synthesis of RuCl₂(CHPh)(PCy₃)(IMes)

RuCl₂(CHPh)(PCy₃)(IMes) was synthesized as described in Jafarpour,Organometallics, 2000, 19, 2055-2057. In a glovebox, a 50 mL roundbottom flask was charged with Grubbs 1st generation (1.5 g, 1.82 mmol),IMes.HCl (933 mg, 2.73 mmol), KOtBu (450 mg, 4.0 mmol) and anhydroushexane (15 mL). The flask was sealed and removed from the gloveboxbefore stirring at 50° C. for 5 h. The resulting suspension was cooledto room temperature and filtered through a collection frit. Theprecipitate was finally washed with water and a minimal amount of hexanebefore being dried under vacuum to afford the desiredRuCl₂(CHPh)(PCy₃)(IMes) as a purple-brown solid (846 mg, 1.0 mmol, 67%yield). The NMR data are in agreement with the literature values.

(ii) Synthesis of RuCl₂(CHPh)(Py)₂(IMes)

RuCl₂(CHPh)(Py)₂(IMes) was synthesized as described in Sanford,Organometallics, 2001, 20, 5314-5318. In a glovebox,RuCl₂(CHPh)(PCy₃)(IMes) (846 mg, 1 mmol) was dissolved in anhydroustoluene (2.5 mL) and pyridine (6.5 mL). The reaction mixture was stirredfor 30 min at room temperature. During that time, a quick change incolor from red to green could be observed. The reaction mixture was thenconcentrated under vacuum before pentane was added. The green residuewas triturated in pentane and allowed to precipitate for 30 minutes at−20° C. The precipitate was then filtered, washed with cold pentane(−20° C.) and finally dried under vacuum to affordRuCl₂(CHPh)(Py)₂(IMes) as a green solid (689 mg, 0.95 mmol, 95% yield).The NMR data are in agreement with the literature values.

(iii) Synthesis of RuCl₂(CHPh)(IMes)₂

RuCl₂(CHPh)(IMes)₂ was synthesized as described in Bantreil, Nat.Protoc., 2011, 6, 69-77. In a glovebox, a 100 mL round bottom flask wascharged with RuCl₂(CHPh)(Py)₂(IMes) (944 mg, 1.30 mmol), IMes (397 mg,1.30 mmol) and anhydrous benzene (50 mL). The brown reaction mixture wasstirred overnight at room temperature, filtered and concentrated undervacuum. The crude residue was then precipitated from cold pentane (−20°C.), filtered and washed with cold pentane (−20° C.). To improve itspurity, the complex was extracted multiple times with boiling hexanes.The precipitate was therefore taken up in boiling hexanes and filtratedthrough a collection frit. This was repeated multiple times to recovermost of the desired complex. The combined organic layers were finallyconcentrated under vacuum to afford the desired RuCl₂(CHPh)(IMes)₂ as abrown solid (670 mg, 0.77 mmol, 59% yield). The NMR data are inagreement with the literature values.

B. Synthesis of RuCl₂ (CHPh)(SIMes)₂

(i) Synthesis of RuCl₂(CHPh)(Py)₂SIMes

RuCl₂(CHPh)(Py)₂(SIMes) was synthesized as described in Sanford citedabove. In a glovebox, Grubbs 2nd generation (250 mg, 294 μmol) wasdissolved in anhydrous toluene (750 μL) and pyridine (1.8 mL). Thereaction mixture was stirred for 30 min at room temperature. During thattime, a quick change in color from red to green could be observed. Thereaction mixture was then poured into cold pentane (−20° C.) inducingprecipitation of a green solid. The solid was allowed to fullyprecipitate for 30 minutes at −20° C. before being filtered, washed withcold pentane (−20° C.) and finally dried under vacuum to affordRuCl₂(CHPh)(Py)₂(SIMes) as a green solid (196 mg, 270 μmol, 92% yield).The NMR data are in agreement with the literature values.

(ii) Synthesis of RuCl₂(CHPh)(SIMes)₂

RuCl₂(CHPh)(SIMes)₂ was prepared as described in Trnka, J. Am. Chem.Soc., 2003, 125, 2546-2558. In a glovebox, a 25 mL round bottom flaskwas charged with RuCl₂(CHPh)(Py)₂(SIMes) (196 mg, 270 μmol), SIMes (83mg, 270 mmol) and benzene (9 mL). The brown reaction mixture was stirredat 45° C. for 24 h before being cooled to room temperature andconcentrated under vacuum. The crude residue was then precipitated fromcold pentane (−20° C.), filtered and washed with cold pentane (−20° C.).To improve its purity, the complex was extracted multiple times withboiling hexanes. The precipitate was therefore taken up in boilinghexanes and filtrated through a collection frit. This was repeatedmultiple times to recover most of the desired complex. The combinedorganic layers were finally concentrated under vacuum to furnish thedesired RuCl₂(CHPh)(SIMes)₂ as a brown solid (150 mg, 171 μmol, 63%yield). The NMR data are in agreement with the literature values.

Cyclic Voltammetry Studies

Cyclic voltammetry studies were run using a glassy carbon electrode, aplatinum wire counter electrode and an Ag/AgCl reference electrode. Forall studies, tetrabutylammonium hexafluorophosphate was used as theelectrolyte in a solution of dichloromethane (RuCl₂(CHPh)(IMes)₂ andRuCl₂(CHPh)(SIMes)₂) or tetrahydrofuran (free IMes and free SIMes) whilenitrogen was bubbled through the solution prior to data collection.Sweeps were run negative (reductive) on first pass.

The cyclic voltammograms of ruthenium complexes RuCl₂(CHPh)(IMes)₂ andRuCl₂(CHPh)(SIMes)₂ both display a pseudo-reversible oxidation at 0.47 V(0.44 V vs SCE) and 0.49 V (0.43 V vs SCE), respectively, which are mostprobably related to the Ru(II)/Ru(III) couple. In addition, oxidationevents at high potentials (>1.8 V) are also observed on both cyclicvoltammograms and are probably related to the oxidation of the carbeneligands. See, Tomar, Chem. Commun., 2018, 54, 9753-9756. These oxidationevents do not appear to be reversible. While the first oxidation processshould be accessible by most Ru- and Ir-based photocatalysts, the eventsat high potentials are only accessible by much oxidizing photocatalystssuch as acridinium and pyrylium derivatives. As described on the nextpage, only those highly oxidizing photocatalysts display somereactivity.

Mechanistic Discussion

Proposed Mechanistic Cycle

Evaluation of the optimized conditions and cyclic voltammetry supportthe above mechanisms. Given the high oxidation potential of the Rucatalyst and the necessity of a highly oxidizing photocatalyst wepropose oxidation of the IMes ligand to liberate the active Ru(II)catalyst. Literature precedent of analogous redox couples with TPPTinvoke formation of intermediate VII. See, Ogawa, J. Am. Chem. Soc.,2015, 137, 1400-1403.

Upon decomplexation, the ground state of TPPT is regenerated and theIMes can coordinate to IV. This complex formation between the reducedTPPT and oxidized IMes rationalizes the imperfect temporal control (0-3%increase during dark periods). TPPT is the optimal catalyst because itis highly oxidizing and lewis acidic, which is accounted for in theproposed mechanism.

NMR experiments probe the nature of the Ru catalysts/TPPT before andafter light. A 1:1 solution of the TPPT/Ruthenium catalyst was evaluatedover a 36 h period with 1H NMRs recorded every 10 min. Upon irradiationwith blue light (5 min) NMR experiments were performed. Diagnostic TPPTpeaks have diminished/broadened in the aromatic range. Over the courseof the kinetic study new peaks appear to form ˜4.8 ppm and ˜8.0-8.1 ppmas TPPT appears to disappear after light irradiation. We believe thiscould be due to complexation between the TPPT and the IMes ligand toform intermediate VII. Further mechanistic studies are currentlyunderway that model the reaction conditions more closely.

Comparison of Ruthenium and TPPT Catalysts Prior and after Blue LightIrradiation.

The ¹H-NMR spectra of the following solutions were obtained andcompared.

See, FIGS. 16-19.

(a) 1:1 TPPT RuCl₂(CHPh)(IMes)₂, 24 hours, after light

(b) 1:1 TPPT ruthenium catalyst, 1 minute after light

(c) 1:1 TPPT ruthenium catalyst, prior to light

(d) TPPT

(e) ruthenium catalyst

These results illustrate that TPPT may complex to the ruthenium catalystto form an intermediate VII.

Extended Optimization Studies: Screening of Photocatalysts

TABLE 3

Excited state oxidation Excited state potential energy YieldPhotocatalyst (V vs. SCE) (kcal/mol) (%) Ir(ppy)₃ 0.31 55.20 0[Ir(ppy)₂(dtbbpy)]PF₆ 0.66 49.21 0 Ru(bpy)₃Cl₂ 0.77 46.49 0 Fluorescein0.77 44.74 0 Rose Bengal 0.81 41.51 0 Eosin Y 0.83 44.05 0 Rhodamine B0.084 41.51 0 Rhodamine 6G 0.95 48.20 0 Ir(dF—CF₃ppy)₂(dtbbpy)]PF₆ 1.2160.10 0 4CzIPN 1.35 n/a 0 Ru(bpz)3Cl₂ 1.45 48.38 0 TAPT 1.84 S₁: 53.96;T₁: 50.96 0 MesAcrPhBFr 2.12 n/a 33 MesAcrMeClO₄ 2.18 S₁: 61.57; T₁:44.74 8 MesAcrMeBF₄ 2.18 S₁: 61.57; T₁: 44.74 16 TPPT 2.55 S₁: 65.26;T₁: 53.04 84

Some known triplet sensitizers such as benzophenone,4,4′-dimethoxybenzophenone, 4,4′-bis(dimethylamino)benzophenone (orMichler's ketone) and 9-fluorenone have also been investigated topromote the ring closing metathesis of diallyl diethylmalonate. As formost photocatalysts displayed in the above chart, no reaction wasobserved. See, Table 3.

On/Off Experiments: On/off experiments were performed for the ringclosing metathesis of diethyl diallylmalonate using 2 mol % ofRuCl₂(CHPh)(IMes)₂ and 4 mol % of 2,4,6-triphenylpyryliumtetrafluoroborate (TPPT) in CH₂Cl₂ (0.2M) at room temperature over aperiod of time alternating cycles of irradiation and darkness. Thereaction was conducted in the presence of mesitylene, used as internalstandard. Aliquots were taken every hour and yields were determined by¹H NMR. On/off experiments were also performed with for the RCM ofdibenzyl diallylmalonate to provide 75% yield in 3.5 h. The on and offstudy is shown in FIG. 9D.

Extended Substrate Scope

These two tables display the synthesis of small molecules.

TABLE 4 Entry Substrate Product Yield^([b]) (%)  1

86  2

84  3

Trace  4

90  5^([c])

89  6

72  7^([c, d])

60  g^([c, d])

70  9^([c, d])

46 10^([c,) ^(c])

51 ^([a])Conditions: substrate (0.2 mmol), RuCl₂(CHPh)(IMes)₂ (2 mol %),TPPT (3 mol %), CH2Cl₂ (0.2M), rt, blue LEDs, 4 h. ^([b])Isolatedyields. ^([c])4 mol % of TPPT. ^([d])Top substrate (0.2 mmol), bottomsubstrate (0.4 mmol), ^([e])Top substrate (0.2 mmol), bottom substrate(0.6 mmol).

TABLE 5 Yield^([b]) Entry Substrate Product (%)  1

80  2

85  3

79  4

71  5^([c])

 0  6

 0  7^([c])

40  8^([c ,d])

50  9^([c ,d])

52 10^([c, d])

60 10^([c, d])

51 11^([c,) ^(e])

53 12^([c,) ^(e])

58 13

<5 14

 0 15

<1 16

<1 17

20 18

10 19

22 20

 5 21

 0 22

 5 23

 5 24

21 25

 8 26

<10  27

74 28

 0 29

18 30

 0 31

 0 32

 0 33

30 34

30 35

13 36

 6 37

60 38

10-20 39

25 40

 4 41

 0 42

 0 43

25 44

 0 45

18 20 24 12 46

<30  47

 5-10 48

 0 49

 0 50

 0 51

10 52

20 53

22 54

36 55

<40 

56

 8 57

 0 58

 0 59

 0 60

 0 61

 0

Scope of the Reaction: Ring-Opening—Cross-Metathesis

The tandem ring-opening—cross-metathesis has also been evaluatedstarting from several cyclic alkenes and proved to be quite successfulin some cases (Scheme 1). The ROCM of cyclooctene withcis-1,4-diacetoxy-2-butene, methyl acrylate and tert-butyl acrylateafforded the desired products in fair yields (53%, 51% and 43%respectively). The use of hex-5-en-1-yl acetate afforded a mixture ofinseparable mono- and bis-coupled products with an overall yield below50%. On the other hand, the use of exo-di-substituted norbornenes onlyled to polymerization with full conversion of the starting materials andno desired products observed. The ROCM of norbornene itself withcis-1,4-diacetoxy-2-butene and methyl acrylate only led to poor yieldsof the desired products (20% and 28% respectively). Finally, the ROCM ofcyclopentene with cis-1,4-diacetoxy-2-butene led to the formation of thedesired product in less than 30% yield whereas the use of methylacrylate afforded the corresponding product in a 58% yield.

Experimental Setups

Experimental Setup 1: Visible-Light-Controlled Olefin Metathesis

The experimental setup includes a magnetic stirrer placed in a cardboardbox, two blue Kessil LED lamps (440 nm) as light sources and a fan tomaintain the reaction mixture at room temperature. The Kessil lamps areplaced at a distance of 5-10 cm from the vial.

Experimental Setup 2: Polymer Patterning Using Macroscopic Photomasks

The polymer patterning experiments using macroscopic photomasks areconducted in a glovebox. The experimental setup includes: a BRAND® petridish (glass) in which the polymerization is performed, a blue Kessil LEDlamp (440 nm) as the light source, a black paper photomask with theappropriate pattern and a fan to maintain the reaction mixture at roomtemperature. The Kessil lamp is placed at a distance of 5-10 cm from thepetri dish.

Experimental Setup 3: Polymer Patterning Using Blue Laser

The polymer patterning experiments using blue lasers are conducted in aglovebox. The experimental setup includes: a BRAND® petri dish (glass)in which the polymerization is performed, a blue laser pointer (450 nm,200 mW) as the light source and a magnifying glass to focus the laserbeam. The support stand is moved either manually or with an orbitalshaker to induce patterning. The blue laser is placed at a distance of5-10 cm from the petri dish.

Experimental Setup 4: Photolithography on Silicon Wafers

The photolithographic experiments on silicon wafers are conducted in aglovebox. The experimental setup includes: anorbornene-pre-functionalized silicon wafer, two microscope slides (22mm×22 mm, thickness of 0.13-0.17 mm), a blue Kessil LED lamp (440 nm) asthe light source, a high resolution photomask and a fan to maintain thesystem at room temperature. The Kessil lamp is placed at a distance of5-10 cm from the silicon wafer.

Experimental Procedures and Characterization Data:

Metathesis for the Synthesis of Small Molecules

General Procedure A: Ring Closing and Enyne Metathesis

In a glovebox, an oven-dried 1-dram vial was charged with the substrate(0.2 mmol), 2,4,6-triphenylpyrylium tetrafluoroborate TPPT (2.4 mg, 6μmol unless otherwise noted), CH₂Cl₂ (1 mL) and RuCl₂(CHPh)(IMes)₂ (3.5mg, 4 μmol). The vial was tightly sealed and removed from the gloveboxbefore stirring at room temperature under blue LEDs irradiation for 4 h(experimental setup 1). The reaction mixture was then concentrated undervacuum and purified by flash column chromatography over silica gel.

General Procedure B: Cross-Metathesis

In a glovebox, an oven-dried 1-dram vial was charged with the limitingolefin (0.2 mmol), 2,4,6-triphenylpyrylium tetrafluoroborate TPPT (3.2mg, 8 μmol), CH₂Cl₂ (1 mL), the excess olefin (0.4 mmol) andRuCl₂(CHPh)(IMes)₂ (3.5 mg, 4 μmol). The vial was tightly sealed andremoved from the glovebox before stirring at room temperature under blueLEDs irradiation for 4 h (experimental setup 1). The reaction mixturewas then concentrated under vacuum and purified by flash columnchromatography over silica gel.

General Procedure C: Ring Opening—Cross-Metathesis

In a glovebox, an oven-dried 1-dram vial was charged with the cyclicolefin (0.2 mmol), 2,4,6-triphenylpyrylium tetrafluoroborate TPPT (3.2mg, 8 μmol), CH₂Cl₂ (1 mL), the terminal olefin (0.6 mmol) andRuCl₂(CHPh)(IMes)₂ (3.5 mg, 4 μmol). The vial was tightly sealed andremoved from the glovebox before stirring at room temperature under blueLEDs irradiation for 4 h (experimental setup 1). The reaction mixturewas then concentrated under vacuum and purified by flash columnchromatography over silica gel.

Diethyl cyclopent-3-ene-1,1-dicarboxylate. Prepared according to GeneralProcedure A. Yield: 86% (36.7 mg, 173 μmol) from diethyldiallylmalonate, 80% (34.1 mg, 161 μmol) from diethyl2-allyl-2-(3-methylbut-2-en-1-yl)malonate and 85% (36.2 mg, 170 μmol)from diethyl 2,2-bis-(but-2-enyl)malonate. Solvent system for flashcolumn chromatography: hexanes/EtOAc: 95/5; Pale yellow oil. Thiscompound has been previously reported. See, Yao, J. Am. Chem. Soc.,2004, 126, 74-75.

Dibenzyl cyclopent-3-ene-1,1-dicarboxylate. Prepared according toGeneral Procedure A. Yield: 79% (53.4 mg, 159 μmol). Solvent system forflash column chromatography: hexanes/EtOAc: 95/5; Colorless oil. ¹H NMR(500 MHz, CDCl₃): δ 7.36-7.24 (m, 10H), 5.62 (s, 2H), 5.14 (s, 4H), 3.07(s, 4H); ¹³C NMR (125 MHz, CDCl₃): δ 171.9, 135.6, 128.6, 128.3, 128.1,127.9, 67.3, 59.0, 41.0; IR (ATR): v_(max) 3063, 2926, 1756, 1724, 1459,1246, 1163, 1062, 975, 731, 694, 453 cm-1; ESIHRMS m/z calcd forC₂₁H₂₁O₄ [M+H]+ 337.1434, found 337.1440.

Diethyl 3-methylcyclopent-3-ene-1,1-dicarboxylate. Prepared according toGeneral Procedure A. Yield: 84% (38.2 mg, 169 μmol). Solvent system forflash column chromatography: hexanes/EtOAc: 95/5; Colorless oil. Thiscompound has been previously reported. See, Xi, Org. Lett., 2007, 9,3259-3261.

1-Tosyl-2,5-dihydro-1H-pyrrole. Prepared according to General ProcedureA.

Yield: 90% (40.2 mg, 180 μmol). Solvent system for flash columnchromatography: hexanes/EtOAc: 90/10; White solid. This compound hasbeen previously reported. See, Hongfa, Org. Lett., 2007, 9, 3259-3261.

1-Tosyl-1,2,3,6-tetrahydropyridine. Prepared according to GeneralProcedure A using 2 μmol of RuCl₂(CHPh)(IMes)₂ and 4 μmol of TPPT.Yield: 74% (35.3 mg, 149 μmol). Solvent system for flash columnchromatography: hexanes/EtOAc: 90/10; White solid. This compound hasbeen previously reported. See, Lipschutz, J. Org. Lett., 2011, 76,4379-4391.

1-Tosyl-2,3,6,7-tetrahydro-1H-azepine. Prepared according to GeneralProcedure A using 2 μmol of RuCl₂(CHPh)(IMes)₂ and 4 μmol of TPPT.Yield: 89% (45.0 mg, 179 μmol). Solvent system for flash columnchromatography: hexanes/EtOAc: 95/5; White solid. This compound has beenpreviously reported. See, Wu, Eur. J. Org. Chem., 2012, 6777-6784.

2-Phenyl-3,6-dihydro-2H-pyran. Prepared according to General ProcedureA. Yield: 72% (23.0 mg, 143 μmol). Solvent system for flash columnchromatography: hexanes/EtOAc: 97/3; Colorless oil. This compound hasbeen previously reported. See, Broggi, Chem. Eur. J., 2010, 16, 9215,9225.

2-Phenyl-2,5-dihydrofuran. Prepared according to General Procedure A.Yield: 71% (20.8 mg, 142 μmol). Solvent system for flash columnchromatography: hexanes/EtOAc: 97/3; Colorless oil. This compound hasbeen previously reported. See, Munoz, Adv. Synth. Catal., 2010, 352,2189-2194.

3-(Prop-1-en-2-yl)-1-tosyl-2,5-dihydro-1H-pyrrole. Prepared according toGeneral Procedure A using 2 μmol of RuCl₂(CHPh)(IMes)₂ and 4 μmol ofTPPT. Yield: 40% (21.1 mg, 80 μmol). Solvent system for flash columnchromatography: hexanes/EtOAc: 97/3; White solid. This compound has beenpreviously reported. See, Fürstner, Chem. Eur. J., 2001, 7, 3236-3253.

Methyl (E)-4-phenylbut-2-enoate. Prepared according to General ProcedureB using allyl benzene (0.2 mmol) and methyl acrylate (0.4 mmol). Yield:60% (21.3 mg, 121 μmol). Solvent system for flash column chromatography:hexanes/EtOAc: 95/5; Pale yellow oil. This compound has been previouslyreported. See, Wang, J. Am. Chem. Soc., 2007, 129, 276-277.

tert-Butyl (E)-4-phenylbut-2-enoate. Prepared according to GeneralProcedure B using allyl benzene (0.2 mmol) and tert-butyl acrylate (0.4mmol). Yield: 50% (22.0 mg, 101 μmol). Solvent system for flash columnchromatography: hexanes/EtOAc: 95/5; Pale yellow oil. This compound hasbeen previously reported. See, Bunnage, Tetrahedron, 1994, 50,3975-3986.

(E)-6-(tert-Butoxy)-6-oxohex-4-en-1-yl benzoate. Prepared according toGeneral Procedure B using pent-4-en-1-yl benzoate (0.2 mmol) and methylacrylate (0.4 mmol). Yield: 52% (25.8 mg, 104 μmol). Solvent system forflash column chromatography: hexanes/EtOAc: 90/10; Yellow oil. Thiscompound has been previously reported. See, Busque, Tetrahedron, 1995,51, 1503-1508.

(E)-4-Phenylbut-2-en-1-yl acetate. Prepared according to GeneralProcedure B using allyl benzene (0.2 mmol) andcis-1,4-diacetoxy-2-butene (0.4 mmol). Yield: 60% (E/Z: 9/1, 23.0 mg,121 μmol). Solvent system for flash column chromatography:hexanes/EtOAc: 95/5; Colorless oil. This compound has been previouslyreported. See, Henderson, Org. Lett., 2010, 12, 824-827.

(E)-5-Acetoxypent-3-en-1-yl benzoate. Prepared according to GeneralProcedure B using but-3-en-1-yl benzoate (0.2 mmol) andcis-1,4-diacetoxy-2-butene (0.4 mmol). Yield: 70% (E/Z: 9/1, 34.9 mg,703 μmol). Solvent system for flash column chromatography:hexanes/EtOAc: 85/15; Colorless oil; ¹H NMR (500 MHz, CDCl₃): E isomer δ8.05 (app. d, J=8.3 Hz, 2H), 7.58 (app. tt, J=7.4 and 1.3 Hz, 1H), 7.46(t, J=8.1 Hz, 2H), 5.85 (dtt, J=15.5, 6.6 and 1.2 Hz, 1H), 5.75 (dtt,J=15.5, 6.3 and 1.3 Hz, 1H), 4.55 (dd, J=6.3 and 0.9 Hz, 2H), 4.39 (t,J=6.5 Hz, 2H), 2.56 (qd, J=6.7 and 1.1 Hz, 2H), 2.06 (s, 3H); ¹³C NMR(75 MHz, CDCl₃): δ 170.9, 166.6, 133.2, 131.1, 130.4, 129.7, 128.4,127.0, 64.9, 63.8, 31.9, 21.1; IR (ATR): v_(max) 2939, 1717, 1451, 1379,1271, 1229, 1111, 1026, 968, 712 cm⁻¹; ESIHRMS m/z calcd for C₁₄H₁₆O₄Na[M+Na]+271.0941, found 271.0946.

(E)-3-(2-Fluorophenyl)allyl acetate. Prepared according to GeneralProcedure B using 2-fluorostyrene (0.2 mmol) andcis-1,4-diacetoxy-2-butene (0.4 mmol). Yield: 51% (20.1 mg, 103 μmol).Solvent system for flash column chromatography: hexanes/EtOAc: 90/10;Colorless oil. This compound has been previously reported.21(E)-6-(2-Fluorophenyl)hex-5-en-1-yl acetate. Prepared according toGeneral Procedure B using 2-fluorostyrene (0.2 mmol) and hex-5-en-1-ylacetate (0.4 mmol). Yield: 46% (21.7 mg, 92 μmol). Solvent system forflash column chromatography: hexanes/EtOAc: 96/4; Colorless oil; ¹H NMR(500 MHz, CDCl₃): δ 7.42 (td, J=7.7 and 1.7 Hz, 1H), 7.19-7.13 (m, 1H),7.06 (td, J=7.4 and 1.0 Hz, 1H), 7.00 (ddd, J=10.9, 8.1 and 1.1 Hz, 1H),6.55 (d, J=15.8 Hz, 1H), 6.28 (dt, J=15.9 and 7.1 Hz, 1H), 4.09 (t,J=6.6 Hz, 2H), 2.27 (qd, J=7.4 and 1.2 Hz, 2H), 2.05 (s, 3H), 1.73-1.66(m, 2H), 1.59-1.52 (m, 2H); ¹³C NMR (125 MHz, CDCl₃): δ 171.3, 160.0 (d,J=246.6 Hz), 133.0 (d, J=4.3 Hz), 128.2 (d, J=8.3 Hz), 127.1 (d, J=3.8Hz), 125.5 (d, J=12.3 Hz), 124.1 (d, J=3.5 Hz), 122.8 (d, J=3.6 Hz),115.7 (d, J=22.1 Hz), 64.4, 33.0, 28.2, 25.7, 21.1; 19F NMR (470 MHz,CDCl₃): δ −119.4 (m); IR (ATR): v_(max) 2934, 1736, 1486, 1365, 1233,1037, 969, 754, 606 cm⁻¹; ESIHRMS m/z calcd for C₁₄H₁₇FO₂Na[M+Na]+259.1105, found 259.1110.

(E)-6-(2-Fluorophenyl)hex-5-en-1-yl acetate. Prepared according toGeneral Procedure B using 2-fluorostyrene (0.2 mmol) and hex-5-en-1-ylacetate (0.4 mmol). Yield: 46% (21.7 mg, 92 μmol). Solvent system forflash column chromatography: hexanes/EtOAc: 96/4; Colorless oil; ¹H NMR(500 MHz, CDCl₃): δ 7.42 (td, J=7.7 and 1.7 Hz, 1H), 7.19-7.13 (m, 1H),7.06 (td, J=7.4 and 1.0 Hz, 1H), 7.00 (ddd, J=10.9, 8.1 and 1.1 Hz, 1H),6.55 (d, J=15.8 Hz, 1H), 6.28 (dt, J=15.9 and 7.1 Hz, 1H), 4.09 (t,J=6.6 Hz, 2H), 2.27 (qd, J=7.4 and 1.2 Hz, 2H), 2.05 (s, 3H), 1.73-1.66(m, 2H), 1.59-1.52 (m, 2H); ¹³C NMR (125 MHz, CDCl₃): δ 171.3, 160.0 (d,J=246.6 Hz), 133.0 (d, J=4.3 Hz), 128.2 (d, J=8.3 Hz), 127.1 (d, J=3.8Hz), 125.5 (d, J=12.3 Hz), 124.1 (d, J=3.5 Hz), 122.8 (d, J=3.6 Hz),115.7 (d, J=22.1 Hz), 64.4, 33.0, 28.2, 25.7, 21.1; 19F NMR (470 MHz,CDCl₃): δ −119.4 (m); IR (ATR): v_(max) 2934, 1736, 1486, 1365, 1233,1037, 969, 754, 606 cm⁻¹; ESIHRMS m/z calcd for C₁₄H₁₇FO₂Na[M+Na]+259.1105, found 259.1110.

Dimethyl (2E,10E)-dodeca-2,10-dienedioate. Prepared according to GeneralProcedure C using cis-cyclooctene (0.2 mmol) and methyl acrylate (0.6mmol). Yield: 51% (26.0 mg, 102 μmol). Solvent system for flash columnchromatography: hexanes/EtOAc: 90/10; Pale yellow oil; ¹H NMR (500 MHz,CDCl₃): δ 6.95 (dt, J=15.5 and 6.9 Hz, 2H), 5.81 (dt, J=15.6 and 1.5 Hz,2H), 3.72 (s, 6H), 2.19 (qd, J=7.2 and 1.5 Hz, 4H), 1.49-1.40 (m, 4H),1.36-1.27 (m, 4H); ¹³C NMR (125 MHz, CDCl₃): δ 167.3, 149.7, 121.1,51.5, 32.2, 29.0, 28.0; IR (ATR): v_(max) 2927, 2854, 1721, 1656, 1435,1269, 1195, 1178, 1038, 980, 716 cm⁻¹; ESIHRMS m/z calcd for C₁₄H₂₃O₄[M+H]+ 255.1591, found 255.1596.

(2E,10E)-Dodeca-2,10-diene-1,12-diyl diacetate. Prepared according toGeneral Procedure C using cis-cyclooctene (0.2 mmol) andcis-1,4-diacetoxy-2-butene (0.6 mmol). Yield: 53% (E,E/E,Z: 9/1, 30.0mg, 106 μmol). Solvent system for flash column chromatography:hexanes/EtOAc: 95/5; Colorless oil; ¹H NMR (500 MHz, CDCl₃): E/E isomerδ 5.76 (app. dt, J=15.3 and 6.8 Hz, 2H), 5.55 (dtt, J=15.3, 6.5 and 1.3Hz, 2H), 4.50 (dd, J=6.5 and 0.7 Hz, 4H), 2.07-2.01 (m, 4H), 2.06 (obs.s, 6H), 1.42-1.33 (m, 4H), 1.32-1.25 (m, 4H); ¹³C NMR (125 MHz, CDCl₃):δ 171.0, 136.7, 123.9, 65.5, 32.3, 29.1, 28.9, 21.2; IR (ATR): v_(max)2926, 2854, 1737, 1446, 1363, 1228, 1023, 965, 698, 607 cm⁻¹; ESIHRMSm/z calcd for C₁₆H₂₆O₄Na [M+Na]+305.1723, found 305.1729.

Dimethyl (2E,7E)-nona-2,7-dienedioate. Prepared according to GeneralProcedure C using cyclopentene (0.2 mmol) and methyl acrylate (0.6mmol). Yield: 58% (24.5 mg, 115 μmol). Solvent system for flash columnchromatography: hexanes/EtOAc: 90/10; Pale yellow oil. This compound hasbeen previously reported.²²

Experimental Procedure and Characterization Data:

Ring Opening Metathesis Polymerization

General Procedure

In a glovebox, an oven-dried 1-dram vial was charged with the monomer(0.2 mmol), 2,4,6-triphenylpyrylium tetrafluoroborate TPPT (0.79 mg, 2μmol), CD2Cl₂ (1 mL) and RuCl₂(CHPh)(IMes)₂ (0.87 mg, 1 μmol).Mesitylene (27.8 μL, 0.2 mmol) was added and used as internal standardto monitor conversion. The vial was tightly sealed and removed from theglovebox before stirring at room temperature under blue LEDs irradiationfor 1 h (experimental setup 1). The reaction mixture was then pouredinto methanol and the desired polymer was finally isolated byfiltration, washed thoroughly with methanol and pentane and dried undervacuum.

Dicyclopentadiene was polymerized using 0.1 μmol of RuCl₂(CHPh)(IMes)₂and 0.5 μmol of TPPT during 15 minutes.

Poly[bicyclo[2.2.1]hept-2-ene] 1. Conversion: >95%. ¹H NMR (500 MHz,CDCl3): δ 5.34 (br. s, 1H), 5.21 (br. s, 1H), 2.79 (br. s, 1H), 2.43(br. s, 1H), 1.96-1.68 (m, 3H), 1.35 (br. s, 2H), 1.12-0.93 (m, 1H).

Poly[exo,exo-dibenzyl bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylate]2.Conversion: >95%. ¹H NMR (500 MHz, CDCl₃): δ 7.30-7.15 (m, 10H),5.39-5.10 (m, 2H), 5.00-4.70 (m, 4H), 3.56-3.28 (m, 1H), 3.07-2.68 (m,3H), 2.30-1.80 (m, 1H), 1.28-0.99 (m, 1H).

Poly[exo,exo-7-oxabicyclo[2.2.1]hept-5-ene-2,3-diylbis(methylene)diacetate] 3. Conversion: 95%. ¹H NMR (500 MHz, CDCl₃): δ 5.79-5.52 (m,2H), 4.49 (br. s, 1H), 4.24-4.07 (m, 5H), 2.06-2.01 (m, 6H).

Poly[(bicyclo[2.2.1]hept-5-en-2-yloxy)(tert-butyl)dimethylsilane] 4.Conversion: >95%. ¹H NMR (500 MHz, CDCl₃): δ 5.47-5.09 (m, 2H),3.63-3.31 (m, 2H), 3.02-2.32 (m, 2H), 2.21-1.65 (m, 3H), 1.52-1.04 (m,2H), 0.89 (br. s, 9H), 0.02 (br. s, 6H).

Estimation of the Krel Light/Dark for the Polymerization ofDicyclopentadiene 12

Following the general procedure described above, polymerization ofdicyclopentadiene was performed under blue LED irradiation, stoppedafter 90 seconds and immediately quenched by addition of excess ethylvinyl ether. Analysis of the crude reaction mixture by ¹H NMR showed 16%polymerization, which corresponds to 10.666% polymerization per minute(Experiment 1). Additionally, polymerization of dicyclopentadiene hasalso been performed with the reaction mixtures being maintained in thedark (wrapped with thin foil). The reaction mixtures were stirred in thedark for 24 h (less than 5% polymerization observed), 3 days (5%polymerization observed) or 7 days (9% polymerization observed). Fromthe last experiments (9% polymerization observed after 7 days), we canestimate the rate of polymerization in the dark to be 9×10−4%polymerization per minute. The ratio between Experiment 2 and 4(10.6666/9×10−4) gives a krel light/dark of 12,000.

Experimental Procedures and Results:

Polymer Patterning Using Masks

All patterning experiments were run in a glovebox to exclude oxygen andensure good reproducibility. Importantly, performing the reactionoutside the glovebox with no other precautions than flushing thereaction mixture with an argon flow gave identical results.

General Procedures

Dicyclopentadiene 12 as Monomer

In a glovebox, an oven-dried 20 mL scintillation vial was charged with2,4,6-triphenylpyrylium tetrafluoroborate TPPT (2.0 mg, 5 μmol), CH₂Cl₂(3 mL) and RuCl₂(CHPh)(IMes)₂ (0.87 mg, 1 μmol). Dicyclopentadiene (1.32g, 10 mmol) was then added and the solution was transferred into aBRAND® petri dish (glass, 40 mm×12 mm). The petri dish was placed on themask and light was shined through the mask for 15 minutes (experimentalsetup 2). The petri dish was finally removed from the glovebox and theunreacted monomer was thoroughly washed away with dichloromethane toafford the desired patterned poly(dicyclopentadiene).

When the patterning experiments were performed on a bigger scale, theamounts of dicyclopentadiene, catalysts, dichloromethane and the size ofthe petri dish were adjusted as followed: dicyclopentadiene (7.93 g, 60mmol), RuCl₂(CHPh)(IMes)₂ (5.2 mg, 6 μmol), 2,4,6-triphenylpyryliumtetrafluoroborate TPPT (11.9 mg, 30 μmol) and CH₂Cl₂ (26 mL) in a BRAND®petri dish (glass, 80 mm×15 mm). Light was shined for 30 minutes.

Norbornadiene 9 as Monomer

In a glovebox, an oven-dried 20 mL scintillation vial was charged with2,4,6-triphenylpyrylium tetrafluoroborate TPPT (5.9 mg, 15 μmol), CH₂Cl₂(2.5 mL) and RuCl₂(CHPh)(IMes)₂ (6.5 mg, 7.5 μmol). Norbornadiene (1.52mL, 15 mmol) was then added and the solution was transferred into aBRAND® petri dish (glass, 40 mm×12 mm). The petri dish was placed on themask and light was shined through the mask for 1 h (experimental setup2). The petri dish was finally removed from the glovebox and theunreacted monomer was thoroughly washed away with dichloromethane toafford the desired patterned poly(norbornadiene).

1,5-Cyclooctadiene 10 as Monomer

In a glovebox, an oven-dried 20 mL scintillation vial was charged with2,4,6-triphenylpyrylium tetrafluoroborate TPPT (5.0 mg, 12.5 μmol),CH₂Cl₂ (2.5 mL) and RuCl₂(CHPh)(IMes)₂ (5.4 mg, 6.25 μmol).1,5-Cyclooctadiene (1.53 mL, 12.5 mmol) was then added and the solutionwas transferred into a BRAND® petri dish (glass, 40 mm×12 mm). The petridish was placed on the mask and light was shined through the mask for 15minutes (experimental setup 2). The petri dish was finally removed fromthe glovebox and the unreacted monomer was thoroughly washed away withdichloromethane to afford the desired patternedpoly(1,5-cyclooctadiene).

5-Ethylidene-2-Norbornene 11 as Monomer

In a glovebox, an oven-dried 20 mL scintillation vial was charged with2,4,6-triphenylpyrylium tetrafluoroborate TPPT (4.0 mg, 10 μmol), CH₂Cl₂(2.5 mL) and RuCl₂(CHPh)(IMes)₂ (4.3 mg, 5 μmol).5-Ethylidene-2-norbornene (1.34 mL, 10 mmol) was then added and thesolution was transferred into a BRAND® petri dish (glass, 40 mm×12 mm).The petri dish was placed on the mask and light was shined through themask for 15 minutes (experimental setup 2). The petri dish was finallyremoved from the glovebox and the unreacted monomer was thoroughlywashed away with dichloromethane to afford the desired patternedpoly(5-ethylidene-2-norbornene).

The thickness of the patterned polymers can be easily modulated bytuning the time of irradiation, as can be seen on the above picturedisplaying poly(dicyclopentadiene) patterns obtained after 5 minutes(0.2 mm), 15 minutes (1.6-2.0 mm) and 60 minutes (3.8 mm) ofirradiation. All measures were made using an electronic digitalmicrometer).

Experimental Procedure and Results:

Polymer Patterning using Blue Laser

General Procedure

In a glovebox, an oven-dried 20 mL scintillation vial was charged with2,4,6-triphenylpyrylium tetrafluoroborate TPPT (2.0 mg, 5 μmol), CH₂Cl₂(3 mL) and RuCl₂(CHPh)(IMes)₂ (0.87 mg, 1 μmol). Dicyclopentadiene (1.32g, 10 mmol) was then added and the solution was transferred into aBRAND® petri dish (glass, 40 mm×12 mm). Irradiation was carried out witha blue laser pointer (450 nm, 200 mW) through a magnifying glass. Thesupport stand holding the laser was then moved either manually over30-40 minutes or with an orbital shaker for 10 minutes (experimentalsetup 3). The petri dish was finally removed from the glovebox andunreacted monomer was thoroughly washed away with dichloromethane toafford the desired patterned poly(dicyclopentadiene).

Experimental Procedures and Results:

Photolithographic Applications on Silicon Wafers

The strategy exploited for the photolithographic ring-opening metathesispolymerization of norbornadiene onto silicon wafers is similar to thestrategy previously reported by Fourkas and coworkers.²³ First, thefunctionalization of the silicon oxide layer of the silicon wafers withtrichloro(5-norbornen-2-yl)silane was performed in order to attach anorbornene unit at the surface of the wafers. Our standardvisible-light-promoted ring opening metathesis polymerization ofnorbornadiene was then performed on the silicon wafers which covalentlybound to the growing polymer thanks to the norbornene unit present atthe surface. Removal of the unreacted monomer finally afforded thedesired patterned poly(norbornadiene) at the surface of the siliconwafers. See, Scheme 2.

Functionalization of Silicon Wafers withTrichloro(5-Norbornen-2-Yl)Silane

Silicon wafers were cleaned by sonication in acetone (2×15 minutes) andisopropanol (2×15 minutes), rinsed with isopropanol, dried under astream of N2 and finally placed in an O₂ plasma chamber under vacuum(100 mTorr) using a power of 50 watts for 2 minutes. The silicon waferswere immediately functionalized with trichloro(5-norbornen-2-yl)silane.

In a glovebox, a 60 mL screw-cap jar was charged with 20 mL of asolution of trichloro(5-norbornen-2-yl)silane (0.2 mL) in anhydroustoluene (20 mL). Four to five 1 cm×1 cm silicon wafers with a nativesilicon oxide layer were added to the solution which was agitatedovernight on an orbital shaker at room temperature. The silicon waferswere then thoroughly rinsed with anhydrous toluene, dried under a streamof N2 and stored in a glovebox prior to use.

Angle contact measurements with a water drop were indicative of thesuccessful grafting of the norbornene unit at the silicon wafer surface(34° for a non-functionalized silicon wafer, 85° for anorbornene-functionalized silicon wafer).

Procedure for the photolithographic patterning ofnorbornene-functionalized silicon wafers

In a glovebox, a norbornene-functionalized silicon wafer was placed on amicroscope slide (22 mm×22 mm, thickness of 0.13-0.17 mm). Four to fivedrops of a solution of norbornadiene (305 μL, 3 mmol),RuCl₂(CHPh)(IMes)₂ (1.3 mg, 1.5 μmol) and 2,4,6-triphenylpyryliumtetrafluoroborate (1.2 mg, 3 μmol) in CH₂Cl₂ (1 mL) were then added tocover the silicon wafer. A second microscope slide (22 mm×22 mm,thickness of 0.13-0.17 mm) was then quickly placed on top of the siliconwafer/solution. The mask was then placed on top of the second microscopeslide and light was shined through the mask for 10 minutes. The siliconwafer was developed by pouring it twice into DCM for 1 minute beforeletting it dry under a steam of N2 to finally afford the desiredpatterned poly(norbornadiene) film.

REFERENCES FOR EXAMPLE 2

1 Cunico, J. Org. Chem. 1971, 36, 929-932.

2 Jafarpour, Organometallics 2000, 19, 2055-2057.

3 (a) Huang, J. Am. Chem. Soc. 1999, 121, 2674-2678. (b) Bantreil, Nat.Protoc. 2011, 6, 69-77.

4 (a) Sanford, Organometallics 2001, 20, 5314-5318. (b) Conrad,Organometallics 2003, 22, 1986-1988.

5 Kotyk, Organometallics 2009, 28, 5424-5431.

6 Trnka, J. Am. Chem. Soc. 2003, 125, 2546-2558.

7 Tomar, Chem. Commun., 2018, 54, 9753-9756.

8 Ogawa, J. Am. Chem. Soc. 2015, 137, 1400-1403

9 Yao, Q.; Zhang, Y. J. Am. Chem. Soc. 2004, 126, 74-75.

10 Xi, Org. Lett. 2011, 13, 6188-6191.

11 Hongfa, Org. Lett. 2007, 9, 3259-3261.

12 Lipshutz, J. Org. Chem. 2011, 76, 4379-4391.

13 Wu, Org. Chem. 2012, 6777-6784.

14 Broggi, Chem. Eur. J. 2010, 16, 9215-9225.

15 Paz Muñoz, Adv. Synth. Catal. 2010, 352, 2189-2194.

16 Fürstner, A.; Chem. Eur. J. 2001, 7, 3236-3253.

17 Wang, S.-Y.; Ji, S.-J.; Loh, T.-P. J. Am. Chem. Soc. 2007, 129,276-277.

18 Bunnage, Tetrahedron 1994, 50, 3975-3986.

19 Busqué, F.; Tetrahedron 1995, 51, 1503-1508.

20 Henderson, Org. Lett. 2010, 12, 824-827.

21 Li, Z.; Zhang, Y.; Liu, Z.-Q. Org. Lett. 2012, 14, 74-77.

22 Hata, Org. Lett. 2008, 10, 5031-5033.

23 Harris, Adv. Matter. 2005, 17, 39-42.

Example 3: Synthesis and Activity of Pyrylium Photocatalysts

A number of pyrylium derivatives with different electron-donating andwithdrawing groups were prepared. Pyryliums 1 and 2 are commerciallyavailable. All pyryliums were previously reported except for pyrylium18. Pyryliums 1-15 and 19-20 were synthesized according to procedurespreviously reported and well established. The procedure for thesynthesis of pyrylium 18 is described herein. These pyrylium derivativesare as identified in Table 6

TABLE 6

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

The new pyrylium compounds were used in the ring closing metathesis ofdiethyl diallylmalonate using (IMes)₂RuCl₂CHPh. See, Scheme 3 and theyields in Table 7.

TABLE 7 Compound Yield Compound Yield

83

0

28

83

85

80

19

83

 3

 2

80

32

83

84

82

48

34

 5

82

80

As can be seen, it seems that, compared to TPPT, new pyryliumspossessing electron-withdrawing groups and some derivatives possessingslightly electron-donating groups are also efficient to promote the RCMof diethyl diallylmalonate.

The same RCM of diethyl diallylmalonate (Scheme 4) was performed withthe photoredox catalysts using TPPT and those in Table 8.

TABLE 8

PC₁

PC₂

PC₃

PC₄

PC₅

PC₆

As noted in Table 9 below, RCM was successful with (OMe)IMes₂RuCl₂CHPhas well.

TABLE 9 Deviation from Standard Entry Conditions Yield (%) 1 none 90 2No light, 24 hours  0 3 No light, no photoredox 70 catalyst, 80° C., 24hours 4 PC₁ 29 (28) 5 PC₂ 62 (83) 6 PC₃  8 (3) 7 PC₄ 23 (32) 8 PC₅  7(2) 9 PC₆ 35 (48)

Example 4: Synthesis of Ru Catalysts

A. Synthesis of (OMe)IMes₂RuCl₂CHPh

Step 1: In a glovebox, a 25 mL round bottom flask was charged withGrubbs 1st generation (206 g, 0.25 mmol), (OMe)IMes.HCl (140 mg, 0.375mmol), KO^(t)Bu (42 mg, 0.375 mmol) and anhydrous toluene (10 mL). Theflask was sealed and removed from the glovebox before stirring at 50° C.for 2 h. The reaction mixture was cooled to room temperature andconcentrated under vacuum. The crude residue was finally washed withwater and a minimal amount of hexane before being dried under vacuum toafford the desired (OMe)IMesRu(PCy₃)Cl₂CHPh as a purple-brown solid (185mg, 0.210 mmol, 84% yield).

Step 2: In a glovebox, (OMe)IMesRu(PCy₃)Cl₂CHPh (185 mg, 0.210 mmol) wasdissolved in anhydrous toluene (680 μL) and pyridine (1.35 mL). Thereaction mixture was stirred for 30 min at room temperature. During thattime, a quick change in color from red to green could be observed. Thereaction mixture was then concentrated under vacuum before pentane wasadded. The green residue was triturated in pentane and allowed toprecipitate for 30 minutes at −20° C. The precipitate was then filtered,washed with cold pentane (−20° C.) and finally dried under vacuum toafford (OMe)IMesRu(Py₂)Cl₂CHPh as a green solid (145 mg, 0.192 mmol, 91%yield).

Step 3: In a glovebox, a 5 mL round bottom flask was charged with(OMe)IMes.HCl (52 mg, 0.138 mmol), KOtBu (16 mg, 0.138 mmol) andanhydrous benzene (2.5 mL). The reaction mixture was stirred for 45 minat room temperature in the glovebox before addition of(OMe)IMesRu(Py₂)Cl₂CHPh (105 mg, 0.138 mmol). The brown reaction mixturewas then stirred at 45° C. for 6 h and concentrated under vacuum. Thecrude residue was finally washed with water and a minimal amount ofhexane before being dried under vacuum to afford the desired(OMe)IMes₂RuCl₂CHPh as a brown solid (110 mg, 0.118 mmol, 85% yield).

B. Synthesis of (OMe)SIMes₂RuCl₂CHPh

Step 1: In a glovebox, a 25 mL round bottom flask was charged withGrubbs 1st generation (206 g, 0.25 mmol), (OMe)SIMes.HCl (187 mg, 0.5mmol), KO^(t)Bu (56 mg, 0.5 mmol) and anhydrous toluene (10 mL). Theflask was sealed and removed from the glovebox before stirring at 50° C.for 2 h. The reaction mixture was cooled to room temperature andconcentrated under vacuum. The crude residue was dissolved indichloromethane, washed with water and concentrated under vacuum. Thecrude residue was finally crystallized in hexane, filtered, washed witha minimal amount of hexane and dried under high vacuum to afford thedesired (OMe)SIMesRu(PCy₃)Cl₂CHPh as a red-pink solid (184 mg, 0.209mmol, 83% yield).

Step 2: In a glovebox, (OMe)SIMesRu(PCy₃)Cl₂CHPh (180 mg, 0.204 mmol)was dissolved in anhydrous toluene (500 μL) and pyridine (1.32 mL). Thereaction mixture was stirred for 30 min at room temperature. During thattime, a quick change in color from red to green could be observed. Thereaction mixture was then concentrated under vacuum before pentane wasadded. The green residue was triturated in pentane and allowed toprecipitate for 30 minutes at −20° C. The precipitate was then filtered,washed with cold pentane (−20° C.) and finally dried under vacuum toafford (OMe)SIMesRu(Py₂)Cl₂CHPh as a green solid (155 mg, 0.204 mmol,quant. yield).

Step 3: The synthesis of (OMe)SIMes₂RuCl₂CHPh from 38 mg (0.05 mmol) of(OMe)SIMesRu(PCy₃)Cl₂CHPh proceeds using the same conditions used forthe synthesis of the corresponding (OMe)IMes₂RuCl₂CHPh.

Example 5: Comparative Studies

A. Studies Lacking Light, Photoredox Catalyst, or Ruthenium Catalyst

A series of control experiments was conducted to determine theimportance of light, photoredox catalyst, and ruthenium catalyst. As afirst set of experiments using IMes₂RuCl₂CHPH, the RCM of diethyldiallylmalonate was performed in the absence of light, absence ofruthenium catalyst, and absence of light. See, Scheme 5.

These results show that there is no reaction in the absence ofphotocatalyst at room temperature, light, or ruthenium catalyst. Assuch, the same experiments were performed using SIMes₂RuCl₂CHPh. See,Scheme 6.

These results also show that there is no reaction in the absence ofphotocatalyst at room temperature, light, or ruthenium catalyst.

B. Organic Oxidants

In an effort to probe the importance of the photoredox catalyst, the RCMof diethyl diallylmalonate was performed using TCNE (tetracyanoethylene)or ferrocenium. See, Scheme 7.

As shown in Table 10, ferrocenium resulted in a moderate yield, only inthe presence of light.

TABLE 10 Oxidant Dark/light Yield (%) TCNE (10 mol %) Dark  0 TCNE (10mol %) Light  0 Cp₂FePF₆ (10 mol %) Dark  0 Cp₂FePF₆ (1 equiv.) Dark  0Cp2FePF6 (10 mol %) Light 39

C. Sub-Stoichiometric Experiments

Experiments were run in an effort to determine the impact ofsub-stoichiometric amounts of various norbornene substituted reagents1-5 and using 25 mol % of the ruthenium catalyst and 50 mol % of thephotoredox catalyst. See, Scheme 8.

These results showed that monomers 1 and 2 (exo, exo) only showed onebenzylidene peak corresponding to the starting IMes₂Ru complex (no othersignals) and the two monomers were consumed within an hour. The use ofnorbornene 3 and 25 mol % of Ru led to instantaneous polymerization.Further, monomers 4 and 5 (endo, endo) were not consumed using 25 mol %of Ru even after 4 hours.

Example 6: Reaction Optimization Studies

A. Concentration and Reaction Time Effects

(i) Experiment #1

The influence of concentration and reaction time on the RCM of diethyldiallylmalonate using 5 mol % of ruthenium catalyst and 5 mol % ofphotoredox catalyst was analyzed. See, Scheme 9.

These results illustrate that although 0.1 M is an optimalconcentration, a concentration of 0.2 M gives an acceptable yield. Inaddition, the reaction seems to be done after 6 hours.

(ii) Experiment #2

For these experiments, 5 mol % of the ruthenium catalyst and 7.5 mol %of the photoredox catalyst were used to study the influence of theconcentration and reaction time on the RCM of diethyl diallylmalonate.See, Scheme 10.

These results illustrate that the reaction is complete in minimal timeand that concentrations of 0.1 M and 0.2M are both efficient.

(iii) Experiment #3

The RCM of diethyl diallylmalonate was performed using slight amounts ofmetathesis catalysts (0.1 and 0.05 mol %). See, Scheme 11.

Table 11 illustrates that the conversion and yields were equal andranged from 8 to 33%.

TABLE 11 Ru (mol %) TPPT (mol %) Time (h) Yield (%) 0.1 0.2  4 29 0.10.2 20 33 0.05 0.1  4  8

B. Catalyst Loadings

(i) Experiment #1

These experiments were performed to study the influence of the catalystsloadings on the reaction. See, Scheme 12.

These results illustrate that the use of 5 mol % of Ru and 7.5 mol % ofphotoredox catalyst was optimal. However, reducing the amounts ofcatalysts to 2 mol % of each or to 5 mol % of Ru and 2 mol % of PC stillresulted in fair amounts of product.

TABLE 12 Ru/Photoredox Catalyst Yield Loading (mol %) (conv.)   5/582%/(>99%)   2/2 14% (43%) 2.5/5 67%/(>99%)   5/2  9% (17%) 5.7582%/(>99%)   5/10 50%/(>99%)

(ii) Experiment #2

Additional experiments were performed, reducing the catalysts loadings.Scheme 13.c

In summary, the use of 2 mol % of Ru and 3 mol % of PC is as efficientas the use of 5 mol % of Ru and 7.5 mol % of PC providing that theconcentration is increased to 0.2 M.

Example 7: Photocatalysts Screening

Several photocatalysts were used in the RCM of diethyl diallylmalonate.See, Scheme 14.

The following catalysts have triplet state of similar energy to the Rucatalyst, as well as to the TPPT photocatalyst (53 kcal).

Although some of these photocatalysts have triplet state energies veryclose to the energy of the Ru catalyst, none of the photoredox catalystsaside from pyrylium or acridinium photocatalysts are capable ofpromoting metathesis.

Example 8: ROMP Using a Mask

(i) Test #1

ROMP was performed using a mask and norbornadiene as the monomer.Specifically, the reaction was performed using 0.05 mol % of Ru and 0.1mol % of TPPT during 1 h at high concentration in DCM (6M).

In these conditions, the ROMP using a mask furnishes the correspondingpolymer with the desired special pattern and reduced side-polymerizationin the dark areas. See, FIG. 26.

Test #2

These experiments were performed as described above, but in a glovebox,using norbornadiene, 1,5-cyclooctadiene (COD),5-ethylidene-2-norbornene, N-methyl-5-norbornene-2,3-dicarboximide, anddicyclopentadiene, respectively, and black paper as the mask. Whilenorbornadiene, 1,5-cyclooctadiene (COD) and 5-ethylidene-2-norborneneprovided the desired pattern, N-methyl-5-norbornene-2,3-dicarboximidedid not. See, FIG. 27.

Test #3

Additional patterns were generated using 0.05 mol % of Ru withdicyclopentadiene, as well as 5-ethylidene-2-norbornene, as themonomers. As shown in FIG. 28, the Columbia crown could be obtained withvarying efficiencies using 5-ethylidene-2-norbornene anddicyclopentadiene.

(iv) Test #4

More complex patterns were prepared in a sequential fashion. Theprocedure was performed by 1) creating a first pattern using a firstmask, 2) developing the pattern by washing with DCM, 3) creating asecond pattern using a second mask, and 4) developing the final combinedpattern by washing with DCM. To make the distinction between the twodifferent sub-pattern, the solution of the first polymerization wasdyed. See, FIG. 29.

Example 9: ROMP with a Laser Pointer

These experiments were performed to induce metathesis using blue-lightlaser pointers instead of Kessil lamps. Although the RCM of diethyldiallylmalonate using the laser pointer was unsuccessful, the ROMP ofdicyclopentadiene was successful. Polymerization occurred in 15-20seconds. See. FIG. 30.

Example 10: Synthesis of Photoredox Catalyst

The preparation of pyrylium B is based on a procedure reported in theliterature. See, Org. Lett. 2017, 19, 2989. In a flame dried 250 mLround bottom flask, known pyran-4-one A (1.36 g, 4.42 mmol) wasdissolved in 120 mL of anhydrous THF under argon before addition of asolution of 2-mesitylmagnesium bromide (1M in THF, 23 mL, 23 mmol)dropwise at room temperature. The reaction mixture was stirred at roomtemperature overnight, quenched with saturated aqueous solution of NH₄C₁and 10% HCl (1:1 mixture), extracted with dichloromethane, washed withbrine, dried over magnesium sulfate, filtered and concentrated underhigh vacuum. The crude residue was dissolved in anhydrous diethyl ether(50 mL) and HBF₄.Et₂O complex (730 μL, 5.3 mmol) was added dropwiseleading to precipitation of a red solid. After stirring for 30 minutesto allow complete precipitation, the precipitate was finally collectedby filtration through a glass frit, washed with diethyl ether and driedunder high vacuum to afford the desired pyrylium B as a red solid (51%,1.11 g, 2.21 mmol).

As those skilled in the art will appreciate, numerous modifications andvariations of the present invention are possible in light of theseteachings, and all such are contemplated hereby. For example, inaddition to the embodiments described herein, the present inventioncontemplates and claims those inventions resulting from the combinationof features of the invention cited herein and those of the cited priorart references which complement the features of the present invention.Similarly, it will be appreciated that any described material, feature,or article may be used in combination with any other material, feature,or article, and such combinations are considered within the scope ofthis invention.

The disclosures of each patent, patent application, and publicationcited or described in this document and the references cited therein arehereby incorporated herein by reference, each in its entirety, for allpurposes.

What is claimed is:
 1. A composition for metathesizing a first alkenylor alkynyl group with a second alkenyl or alkynyl group, the compositioncomprising: a ruthenium metathesis catalyst and a photoredox catalystthat is activated by visible light.
 2. The composition of claim 1,wherein the visible light has a wavelength of about 350 nm to about 750nm.
 3. The composition of claim 1, wherein the ruthenium metathesiscatalyst is of Formula (I):

wherein: R¹ is H, C₁₋₆alkyl, C₂₋₆alkenyl, aryl, or heteroaryl; R² to R⁵are, independently in each occurrence, H, C₁₋₆alkyl, C₁₋₆alkoxy, halo,or aryl; and w to z are, independently, 0 to
 5. 4. The composition ofclaim 1, wherein the ruthenium metathesis catalyst is


5. The composition of claim 1, wherein the ruthenium metathesis complexis (IMes)₂RuCl₂CHPh.
 6. The composition of claim 1, wherein thephotoredox catalyst is:


7. A method for chemical metathesis, comprising applying visible lightto (i) one compound comprising a first alkenyl or alkynyl group and asecond alkenyl or alkynyl group or (ii) a first compound comprising afirst alkenyl or alkynyl group and a second compound comprising a secondalkenyl or alkynyl group, in the presence of a ruthenium metathesiscatalyst and a photoredox catalyst that is activated by visible light.8. The method of claim 7, wherein the visible light has a wavelength ofabout 350 nm to about 750 nm.
 9. The method of claim 7, wherein theruthenium metathesis catalyst is of Formula (I):

wherein: R¹ is C₁₋₆alkyl, C₂₋₆alkenyl, aryl, or heteroaryl; R² to R⁵are, independently in each occurrence, C₁₋₆alkyl, C₁₋₆alkoxy, halo, oraryl; and w to x are, independently, 0 to
 5. 10. The method of claim 7,wherein the ruthenium metathesis catalyst is


11. The method of claim 7, wherein the ruthenium metathesis complex is(IMes)₂RuCl₂CHPh.
 12. The method of claim 7, wherein the photoredoxcatalyst is:


13. The method of claim 7, that is performed at a temperature of about20 to about 30° C.
 14. The method of claim 7, comprising about 0.01 toabout 10 mol %, based on the mol % of the one compound or first andsecond compound, of the ruthenium metathesis catalyst.
 15. The method ofclaim 7, wherein the concentration of the one compound or first andsecond compound is about 0.01 to about 5 M.
 16. A method of spatiallycontrolling a metathesis, comprising: forming a mixture of a rutheniummetathesis catalyst, a photoredox catalyst, and one or more compoundssusceptible to metathesis; and applying visible light to one or moreregions of the mixture so as to give rise to one or more metathesizedregions and one or more unmetathesized regions.
 17. The method of claim16, wherein the visible light is applied using a high resolution lightsource.
 18. The method of claim 16, wherein at least one of theunmetathesized regions is covered with a photomask.
 19. The method ofclaim 16, wherein the mixture is disposed on a substrate that isfunctionalized with the one or more compounds susceptible to metathesis.20. A method of spatially controlling a metathesis, comprising: applyingvisible light to a ruthenium metathesis catalyst, a photoredox catalyst,and one or more compounds susceptible to metathesis, the applying beingperformed so as to give rise to one or more metathesized regions, atleast one of the ruthenium metathesis catalyst and the photoredoxcatalyst being linked to a substrate, the substrate optionally beingstationary.
 21. The method of claim 20, wherein the visible light isapplied in a predetermined pattern.